孔
コウ, あな, のり

cavity, hole, slit, very, great, exceedingly

JLPT1 G7 S4 F2052

The relevant seal inscription form is 子 child + a mark# → mother and newborn (just passed through the vagina in being born), connected by the curving and now stretched umbilical cord → *hole* (← vagina). *Confucius* is a borrowed meaning.

[Full Kanji Etymology List]