a word, a shortest part that means something in a sentence

the long-vowel mark (ー), which marks a long vowel in katakana (and less commonly in hiragana) when placed after a syllable

to use / to employ / to make use of, to apply / to spend

use one thing for many purposes / work someone hard

to use one's head

The hiragana syllable げ (ge) or the katakana syllable ゲ (ge) in Japanese braille.