function word
Linguistics term for words that express grammatical relationships rather than concrete meaning, such as particles, auxiliary verbs, and conjunctions. Contrasts with 内容語 (content word).
See also: 内容語
Particles like 'ga' and 'wo' are classified as function words.
Function words are words that play a grammatical role.
Compound of 機能 (function) and 語 (word), a straightforward calque of the English term 'function word'.