中
チュウ, なか, うち, あた.る, あたる, かなえ
in, inside, middle, mean, center
JLPT5 G1 S4 F11
The relevant oracle bone form of this character shows banners centered on the flagpole run through them → *center/middle* → *inside* → *throughout*; *including*; *the mean*.
[Full Kanji Etymology List]