化石
かせき · kaseki · JLPT N1 · noun
dodo
🦕 化 (change into) + 石 (stone) = something that turned into stone
Ancient bones and shells slowly turned into stone over millions of years. The 化 here is the same one in 変化 (change), so the word means a thing that has changed into stone.
化 — person 亻 + spoon/upside-down person 匕
化 is an associative compound showing a standing person 亻 next to 匕, originally a depiction of a person turned upside-down. Together they suggest a figure transforming from one state to another, giving the core meaning 'change' or 'transform'. The character later extended to senses like 'convert', 'influence', and the noun suffix '-ization'.