Kinds

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basic kinds	default value	repeat	props	under
The default value is used when we make something like a variable but don't tell Inform what its value is. For instance, if we write 'Zero hour is a time that varies', but don't tell Inform anything specific like 'Zero hour is 11:21 PM.', then Inform uses the value in the table above to decide what it will be. The same applies if we create a property (for instance, 'A person has a number called lucky number.'). Kinds of value not included in the table cannot be used in variables and properties.
A tick for repeat means that it's possible to repeat through values of this kind. For instance, 'repeat with T running through times:' is allowed, but 'repeat with N running through numbers:' is not - there are too many numbers for this to make sense. A tick here also means it's possible to form lists such as 'list of rulebooks', or to count the 'number of scenes'.
A tick for props means that values of this kind can have properties. For instance, 'A scene can be thrilling or dull.' makes an either/or property of a scene, but 'A number can be nice or nasty.' is not allowed because it would cost too much storage space. (Of course 'Definition:' can always be used to make adjectives applying to numbers; it's only properties which have storage worries.)
A tick for under means that it's possible to understand values of this kind. For instance, 'Understand "award [number]" as awarding.' might be allowed, if awarding were an action applying to a number, but 'Understand "run [rule]" as rule-running.' is not allowed - there are so many rules with such long names that Inform doesn't add them to its vocabulary during play.
object [14]	north
room [1]	Lab
thing [1]	yourself
door	nothing
container	nothing
vehicle	nothing
player's holdall	nothing
supporter	nothing
backdrop	nothing
person [1]	yourself
man	nothing
woman	nothing
animal	nothing
device	nothing
direction [12]	north
region	nothing
number	0
real number	0
time	9:00 AM
truth state	false
text	""
snippet	word 1 of command
unicode character	unicode 32 (a space)
action	waiting
scene[1]	Entire Game
command parser error [25]	didn't understand error
use option	the ineffectual option
response	?
verb	verb be
table name	a table with no rows or columns
equation name	an equation doing nothing
rulebook outcome	allow access
external file	a non-file
action name	waiting action
figure name[1]	Figure of cover
sound name	a silent non-sound
natural language [6]	English language
grammatical tense  [5]	present tense
narrative viewpoint  [6]	first person singular
grammatical case  [2]	nominative
grammatical gender  [3]	neuter gender
making new kinds from old	default value
list of K	{ }
phrase K -> L	always the default value of L
relation of K	a relation never holding
K based rule producing L	the little-used do nothing rule
K based rulebook producing L	the action-processing rules
activity on K	printing the name
description of K	matching nothing
K valued property	--
K valued table column	--

object (plural objects)

Matches: value, sayable value
Objects are values intended to simulate physical things: places, people, things, and so on. They come in many kinds. The special value 'nothing' is also allowed, and can be used to mean 'no object at all'.
Usually singular-named not plural-named, improper-named not proper-named.
Usually not ambiguously plural.
Can have printed name (text), printed plural name (text), indefinite article (text), list grouping key (text).

room (plural rooms)

Represents geographical locations, both indoor and outdoor, which are not necessarily areas in a building. A player in one room is mostly unable to sense, or interact with, anything in a different room. Rooms are arranged in a map.
Usually lighted not dark, unvisited not visited.
Can have description (text), map region (object).

Lab 

thing (plural things)

Represents anything interactive in the model world that is not a room. People, pieces of scenery, furniture, doors and mislaid umbrellas might all be examples, and so might more surprising things like the sound of birdsong or a shaft of sunlight.
Usually unlit not lit, inedible not edible, portable not fixed in place, described not undescribed, unmarked for listing not marked for listing, mentioned not unmentioned.
Usually not scenery, wearable, pushable between rooms, handled.
Can have description (text), initial appearance (text), matching key (object).

door (plural doors)

Represents a conduit joining two rooms, most often a door or gate but sometimes a plank bridge, a slide or a hatchway. Usually visible and operable from both sides (for instance if you write 'The blue door is east of the Ballroom and west of the Garden.'), but sometimes only one-way (for instance if you write 'East of the Ballroom is the long slide. Through the long slide is the cellar.').
Always fixed in place not portable.
Usually closed not open, openable not unopenable, unlocked not locked.
Usually not lockable.
Never pushable between rooms.
Can have leading-through destination (object).

container (plural containers)

Represents something into which portable things can be put, such as a teachest or a handbag. Something with a really large immobile interior, such as the Albert Hall, had better be a room instead.
Usually opaque not transparent, open not closed, unopenable not openable, unlocked not locked.
Usually not enterable, lockable.
Can have carrying capacity (number).

vehicle (plural vehicles)

Represents a container large enough for a person to enter, and which can then move between rooms at the driver's instruction. (If a supporter is needed instead, try the extension Rideable Vehicles by Graham Nelson.)
Always enterable.
Usually fixed in place not portable.

player's holdall (plural player's holdalls)

Represents a container which the player can carry around as a sort of rucksack, into which spare items are automatically stowed away.
Always portable not fixed in place.
Usually openable not unopenable.

supporter (plural supporters)

Represents a surface on which things can be placed, such as a table.
Always transparent not opaque.
Usually fixed in place not portable.
Usually not enterable.
Can have carrying capacity (number).

backdrop (plural backdrops)

Represents an aspect of the landscape or architecture which extends across more than one room: for instance, a stream, the sky or a long carpet.
Always fixed in place not portable.
Usually scenery.
Never pushable between rooms.

person (plural people)

Despite the name, not necessarily a human being, but anything animate enough to envisage having a conversation with, or bartering with.
Always transparent not opaque.
Usually male not female.
Usually not neuter.
Can have carrying capacity (number).

yourself

man (plural men)

Represents a man or boy.
Always male not female.
Never neuter.

woman (plural women)

Represents a woman or girl.
Always female not male.
Never neuter.

animal (plural animals)

Represents an animal, or at any rate a non-human living creature reasonably large and possible to interact with: a giant Venus fly-trap might qualify, but not a patch of lichen.

device (plural devices)

Represents a machine or contrivance of some kind which can be switched on or off.
Usually switched off not switched on.

direction (plural directions)

Represents a direction of movement, such as northeast or down. They always occur in opposite, matched pairs: northeast and southwest, for instance; down and up.
Always scenery.
Usually unmarked for listing not marked for listing.
Can have opposite (direction).

 12 directions

region (plural regions)

Represents a broader area than a single room, and allows rules to apply to a whole geographical territory. Each region can contain many rooms, and regions can even be inside each other, though they cannot otherwise overlap. For instance, the room Place d'Italie might be inside the region 13th Arrondissement, which in turn is inside the region Paris. Regions are useful mainly when the world is a large one, and are optional.

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number (plural numbers)

Matches: value, sayable value, understandable value, arithmetic value
Whole number in the range -32768, -32767, ..., -2, -1, 0, 1, 2, 3, ..., 32767: small numbers can be written textually as 'one', 'two', 'three', ..., 'ten', 'eleven', 'twelve'. (A much larger number range is allowed if we compile the source to Glulx rather than the Z-machine: see the Settings panel.)

real number (plural real numbers)

Matches: value, sayable value, understandable value, arithmetic value, real arithmetic value
A real, or 'floating-point' number: the difference between this and ordinary "number" is that real numbers can hold values like 3.141, which aren't whole numbers, and can also hold very large or very small quantities in an approximate way. (Use of real numbers is only allowed if we compile the source to Glulx rather than the Z-machine: see the Settings panel.)

time (plural times)

Matches: value, sayable value, understandable value, arithmetic value
A time of day, written in the form '2:34 AM' or '12:51 PM', or a length of time such as '10 minutes' or '3 hours 31 minutes', which must be between 0 minutes and 23 hours 59 minutes inclusive.

truth state (plural truth states)

Matches: value, sayable value, understandable value
The state of whether something is 'true' or 'false'. (In other computing languages, this might be called 'boolean', after the 19th-century logician George Boole, who first realised this was a kind of value.)

text (plural texts)

Matches: value, sayable value
Some text in double quotation marks, perhaps with substitutions written in square brackets.

snippet (plural snippets)

Matches: value, sayable value
A fragment of the player's most recent typed command, taking in a run of consecutive words.

unicode character (plural unicode characters)

Matches: value, sayable value
A single character - a letter or item of punctuation.

action (plural actions)

Matches: value, sayable value
A stored action, which can later be tried.

scene (plural scenes)

Matches: value, sayable value, understandable value, enumerated value
Like a scene in a play: a period of time which is usually tied to events in the plot. Scenes are created by sentences like 'Midnight Arrival is a scene.'
Usually non-recurring not recurring.
Can have description (text).

Entire Game

command parser error (plural command parser errors)

Matches: value, sayable value, understandable value, enumerated value

 25 command parser errors

use option (plural use options)

Matches: value, sayable value
One of the optional ways to configure Inform, such as the 'authorial modesty option'.

response (plural responses)

Matches: value, sayable value
One of the standard responses issued by the Standard Rules or other extensions.

verb (plural verbs)

Matches: value, sayable value
One of the verbs which Inform knows how to conjugate.

table name (plural table names)

Matches: value, sayable value
Like tables of information in a book or newspaper, tables in Inform hold values which have been organised into rows and columns. A table name is just a single value, identifying which table is meant - say, 'Table of US Presidents' might be a table name value.

equation name (plural equation names)

Matches: value
Like formulae in a textbook or a scientific paper, equations in Inform are written out in displayed form and given names.

rulebook outcome (plural rulebook outcomes)

Matches: value, sayable value

external file (plural external files)

Matches: value, sayable value, understandable value, enumerated value
When made with the Glulx setting, an Inform project can make limited use of files stored on the computer which is operating the story at run-time. An external-file is just the name of one of these files (not the filename in the usual sense, but a name given to it in the Inform source text).

action name (plural action names)

Matches: value, sayable value
An action is what happens when one of the people in the simulated world decides to do something. A full action would be something like 'dropping the box', but an action name is just the choice of which sort of thing is being done: here, it's 'the dropping action'. (Action names are always written with the word 'action' at the end, to make sure they aren't mistaken for full actions.)

figure name (plural figure names)

Matches: value, sayable value, understandable value, enumerated value
When made with the Glulx setting, an Inform project can include images as well as words, and these are called figures. A figure name is just the name of one of the figures in the current project.

Figure of cover

sound name (plural sound names)

Matches: value, sayable value, understandable value, enumerated value
When made with the Glulx setting, an Inform project can include sound effects or pieces of music. A sound name is just the name of one of these sounds in the current project.

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natural language (plural natural languages)

Matches: value, sayable value, understandable value, enumerated value

English language, French language, German language, Italian language, Spanish language, Swedish language

grammatical tense  (plural grammatical tenses)

Matches: value, sayable value, understandable value, enumerated value

present tense , past tense , perfect tense , past perfect tense , future tense 

narrative viewpoint  (plural narrative viewpoints)

Matches: value, sayable value, understandable value, enumerated value

first person singular , second person singular , third person singular , first person plural , second person plural , third person plural 

grammatical case  (plural grammatical cases)

Matches: value, sayable value, understandable value, enumerated value

nominative , accusative 

grammatical gender  (plural grammatical genders)

Matches: value, sayable value, understandable value, enumerated value

neuter gender , masculine gender , feminine gender 

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list of K (plural lists of K)

covariant >

Matches: value, sayable value
A flexible-length list of values, where all of the items have to have the same kind of value as each other - for instance, a list of rooms, or a list of lists of numbers. The empty list, with no items yet, is written { }, and a list with items in is written with commas dividing them - say {2, 5, 9}.

phrase K -> L (plural phrases K -> L)

contravariant in K, covariant in L >

Matches: value, sayable value

relation of K (plural relations of K)

covariant >

Matches: value, sayable value

K based rule producing L (plural K based rules producing L )

contravariant in K, covariant in L >

Matches: value, sayable value
One of many, many rules which determine what happens during play. Rules can be triggered by scenes beginning or ending, by certain actions, at certain times, or in the course of carrying out certain activities.

K based rulebook producing L (plural K based rulebooks producing L )

contravariant in K, covariant in L >

Matches: value, sayable value
A list of rules to follow, in sequence, to get something done. A rulebook is like a ring-binder, with the individual rules as sheets of paper. Inform normally sorts these into their 'natural' order, with the most specific rules first, but it's easy to shuffle the pages if you need to. When some task is carried out during play, Inform is normally working through a rulebook, turning the pages one by one.

activity on K (plural activities on K )

contravariant >

Matches: value
An activity is something which Inform does as part of the mechanics of play - for instance, printing the name of an object, which Inform often has to do. An activity can happen by itself ('printing the banner text', for instance) or can be applied to an object ('printing the name of something', say).

description of K (plural descriptions of K)

covariant >

Matches: value
A description of a set of values, where all of the items have to have the same kind of value as each other - for instance, 'even numbers' or 'open doors which are in lighted rooms'.

K valued property (plural K valued properties)

covariant >

Matches: value

K valued table column (plural K valued table columns)

covariant >

Matches: value

Covariance means that if K is a kind of L, then something you make from K can be used as the same thing made from L. For example, a list of doors can be used as a list of things, because 'list of K' is covariant. Contravariance means it works the other way round. For example, an activity on things can be used as an activity on doors, but not vice versa, because 'activity of K' is contravariant.

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Kinds of value marked with the calculator symbol are numerical - these are values we can add, multiply and so on. The range of these numbers depends on the Format setting for the project (Glulx format supports much higher numbers than Z-code).

kind of value	minimum	maximum	dimensions
number	1	2147483647	dimensionless
real number	--	--	dimensionless
time	1 minute	23 hours 59 minutes	(time)

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Miscellaneous Definitions
language of play - natural language
parameter-object - object

Situation
player - person
location - object
score - number
last notified score - number
maximum score - number
turn count - number
time of day - time
darkness witnessed - truth state

Current action
noun - object
second noun - object
person asked - object
reason the action failed - rule
item described - object

Used when ruling on accessibility
person reaching - object
container in question - object
supporter in question - object
particular possession - thing

Used when understanding typed commands
player's command - snippet
matched text - snippet
kind understood - value
current item from the multiple object list - object

Presentation on screen
command prompt - text
left hand status line - text
right hand status line - text
listing group size - number

Language generation
prior named object - object

Command parser errors
latest parser error - command parser error

Grammatical definitions
story tense  - grammatical tense
story viewpoint  - narrative viewpoint

List of Named or Numbered Equations (About equations)

None