Word

A word is most simply defined as an element that is listed in the dictionary (= lexeme) or that occurs between two spaces in the spelling or the linguist's description (= word-form).

Words are morphological objects which may but need not be the output of processes of affixation and compounding.

These definitions are of course not satisfactory, because they do not say why linguists enter elements into a dictionary or write them between two spaces etc.

Subtypes

 * lexeme (= a dictionary word)
 * word-form, grammatical word (= a text word, occurring between two spaces)
 * phonological word

In syntax
Words are generally considered atomic elements: they are the indivisible building blocks of syntax, which may be the input but not the output of syntactic processes, their parts presumably being inaccessible for syntactic rules. See lexical integrity.

In phonology
Words are phonological objects which consitute the domain for lexical phonological rules. It is particularly striking that these three uses of the notion 'word' are not co-extensive.

Example
A group consisting of a free morpheme and a clitic may function as a phonological word, although morphologically it is a clitic group consisting of a morphological word and a clitic.

Other languages

 * French mot
 * German Wort

Links
Utrecht Lexicon of Linguistics