呼
コ, よ.ぶ, よぶ

call, call out to, invite

JLPT3 G6 S8 F498

乎# exclamation + 口 mouth (for emphasis/clarification) → *call*; *call out* → *call/send for* → *summon*; *invite* → *bring about*; *arouse*; *attract* (← action that attracts/brings about a response).

[Full Kanji Etymology List]