### Instruction: Define Part of Speech
### Response: In grammar, a part of speech or part-of-speech (abbreviated as POS or PoS, also known as word class or grammatical category) is a category of words (or, more generally, of lexical items) that have similar grammatical properties. Words that are assigned to the same part of speech generally display similar syntactic behavior (they play similar roles within the grammatical structure of sentences), sometimes similar morphological behavior in that they undergo inflection for similar properties and even similar semantic behavior. Commonly listed English parts of speech are noun, verb, adjective, adverb, pronoun, preposition, conjunction, interjection, numeral, article, and determiner.

Almost all languages have the word classes noun and verb, but beyond these two there are significant variations among different languages. For example:

Japanese has as many as three classes of adjectives, where English has one.
Chinese, Korean, Japanese and Vietnamese have a class of nominal classifiers.
Many languages do not distinguish between adjectives and adverbs, or between adjectives and verbs.
Because of such variation in the number of categories and their identifying properties, analysis of parts of speech must be done for each individual language. Nevertheless, the labels for each category are assigned on the basis of universal criteria