公園
こうえん · kouen · JLPT N5 · noun
park
🌳 公園 = public + garden: a garden open to everyone
公 (kou) means public, as in 公共 (public, communal). 園 (en) means garden, as in 動物園 (zoo, literally animal garden). A public garden is a park. The reading kouen is simply the two on-readings joined: kou + en.
公 — eight 八 + private 厶
Originally an ideograph showing 八 (to divide) over 厶 (private/self), depicting the act of splitting away from selfish interest. The combination came to mean 'public' or 'fair,' the opposite of private. It later extended to senses like 'duke,' 'lord,' and 'grandfather.'