同
ドウ, おな.じ

same, agree, equal

JLPT4 G2 S6 F15

The relevant oracle bone form of this character is 用# (run through) + a hole → run a stick through a board, creating a hole → *same*; *equal* (← board with a stick run through it to the point that the same amount of the stick is on each side of the board).

[Full Kanji Etymology List]