parts of speech (POS) and named entities are useful clues to sentence structure and meaning. knowing whether a word is a noun or a verb tells us about likely neighboring words (nouns in English are preceded by determiners and adjectives, verbs by nouns) and syntactic structure (verbs have dependency links to nouns), making part-of-speech tagging a key aspect of parsing. knowing if a named entity like Washington is a name of a person, a place, or a university is important to many natural language understanding tasks like question answering, stance detection, or information extraction.
| tag | description | example |
|---|---|---|
| adj | adjective: noun modifiers describing properties | red,young,awesome |
| adv | adverb: verb modifiers of time, place, manner | very,slowly,home,yesterday |
| noun | words for persons, places, things, etc. | algorithm, cat, mango, beauty |
| verb | words for actions and processes | draw, provide, go |
| propn | proper noun: name of a person, organization, place, etc.. | Regina, IBM, Colorado |
| intj | interjection: exclamation, greeting, yes/no response, etc. | oh, um, yes, hello |
| adp | adposition (preposition/postposition): marks a noun's special, termpoal, or other relation | in, on, by under |
| aux | auxiliary: helping verb making tense, aspect, mood, etc.. | can, may, should, are |
| cconj | coordinating conjunction: joins two phrases/clauses | and, or, but |
| det | determiner: marks noun phrase properties | a, an, the, this |
| num | numeral | one, two, first, second |
| part | particle: a preposition-like form used together with a verb | up, down, on, off, in, out, at, by |
| pron | pronoun: a shorthand for referring to an entity or event | she, who, I, others |
| sconj | subordinating conjunction: joins a main clause with a subordinate clause such as a sequential complement | that, which |
| punct | punctuation | ; , () |
| sym | symbols like $ or emoji | $, % |
| X | other | asdf, qwfg |