Depicts using a staff (丂) for striking. Based on the original meaning "to strike", now written as 抨. The meaning later shifted to "level", "even", and "flat".
Shuowen Jiezi
《說文》：“平，語平舒也。从亏，从八。八，分也。”
Original meaning
to strike
Components
◎(iconic) — Depicts the moving motion of striking.