ヨウ, もち.いる, たから
utilize, business, service, use, employ
JLPT4 G2 S5 F107
The relevant oracle bone form of this character depicts a stick being run through a rectangular board, piercing a hole → *use*; *action* → *have a need* → *go to the toilet* (← have a need to relieve oneself).
[Full Kanji Etymology List]