change; alteration; substitution / instead (of); in place (of); as a substitute (for)

to use one's head

use one thing for many purposes / work someone hard

a letter or character (symbol for a sound or a word) / (linguistics) script, writing system / (specific to Japanese) a written mora, a kana / writing in general, written words

a letter, a character (symbol for a sound or a word) / (linguistics) script, writing system / (specific to Japanese) a written mora, a kana / writing in general, written words

Mongolia

office work / office worker

Synonym of 一層 (issō) or 一層 (isso)

more importantly

one's own concern or problem