About: This page serves to collect descriptive information about number words and their peculiarities in several languages, to support discussion of policy and recommended practice in treatment of number words in all languages in Wiktionary.
Number words include above all words refering to cardinal numbers ("one", "two", "ten", "hundred", "hundreds") and ordinal numbers ("first", "second", "third", "tenth", "hundredth"). Number words can have peculiar grammar, both in English and other languages. In English, "three" is uncountable and behaves a bit like an adjective modifying a plurality rather than the members of the plurality (compare "big apples" vs "three apples", and compare "a set of big apples" vs "a big set of apples" or "three-membered set of apples"), while "hundred" is countable and is used with a determiner. The English ordinals including "third" and "hundredth" behave like adjectives, and so are classed by some English grammars as adjectives.
In some grammars, number words get assigned a dedicated part of speech, called "number" or "numeral". This part of speech can subsume cardinal numbers and ordinal numbers, and some other classes of number words.
Some grammarians, especially non-English ones for non-English languages, can choose to assign also other words than cardinals and ordinals to this part of speech of "number" or "numeral". These other words would in English include "double" (adjective), "triple" (adjective), "doubly", "triply", "twice", "thrice". The concept of whole positive number is contained in the meanings of such words as "duplicate", and "triplicate", furthermore "primary", "secondary", and "tertiary", and also "unary", "binary", and "ternary". A broader concept of number is there in the words referring to fractions, in English "half", "third", "fifth", "tenth", and "two thirds". Some real numbers are referred to by nouns or noun-like terms: "pi" AKA "Ludolph's number". Latin has classes of number words called adverbial, distributive and multiplicative.
Inflection: In some languages, number words show different inflection patterns than adjectives and nouns. In these languages, the inflection pattern of a word is one telltale sign of the word's being a number word.
Number vs numeral: Number words may get called "numbers" or "numerals". Both words are ambiguous: "number" also refers to the meaning of a number word; "numeral" also refers particularly to a symbol that is not a word and represents a number, such as the Arabic numerals 1, 2, 3 and the Roman numerals I, V, X, L.
Set theory: Infinite cardinal numbers and infinite ordinal numbers are arcana of set theory that do not pertain to number words in natural languages. These arcana can be ignored in the discussion of grammar and semantics of natural languages. The following mention is included merely for the sake of completeness. In set theory (a branch of mathematics), cardinal numbers include aleph-null, which is the cardinality of (a formal way of saying "the number of elements of") the set of all positive integers. Set-theoretic ordinal numbers are a rather complex construction that involves things called omega, omega + 1, and epsilon zero.
In Latin, there are not only cardinal and ordinal numerals, but also adverbial, distributive and multiplicative. For an example, see the floating boxes in the entries unus (1), duo (2), tres (3), and quattuor (4).
The content of the floating boxes:
| Cardinal | Ordinal | Adverbial | Multiplier | Distributive |
|---|---|---|---|---|
| unus | primus | semel | simplex | singuli |
| duo | secundus | bis | duplex | bini |
| tres | tertius | ter | triplex | terni |
| quattuor | quartus | quater | quadruplex | quaterni |
A sample of Polish number words, based on W:pl:Liczebnik:
Wiktionary appendices for words refering to numbers (also Category:Numerical appendices):
Grammatical works that deal with part of speech of number words: