noun
: a word expressing primarily grammatical relationship (as a preposition, auxiliary verb, conjunction, conjunctive adverb, or relative) — called also empty word, form word ; compare full word
noun
: a word expressing primarily grammatical relationship (as a preposition, auxiliary verb, conjunction, conjunctive adverb, or relative) — called also empty word, form word ; compare full word
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012