化石 (kaseki) means “fossil” | MotiTan Japanese Dictionary

More examples

これは恐竜の化石です。ko re wa kyō ryū no ka seki de su

This is a dinosaur fossil.

この地層には古代の生物の化石が含まれています。ko no chi sō ni wa ko dai no sei butsu no ka seki ga fuku ma re te i ma su

This rock layer contains fossils of ancient organisms.

Describes a trace of ancient life preserved in layers of earth, often through a slow process that makes it rocklike.

地質時代の生物の体や足跡などが地層に保存されたもの。chi shitsu ji dai no sei butsu no karada ya ashi ato na do ga chi sō ni ho zon sa re ta mo no

化石 (kaseki) combines 化 (ka, "transformation") with 石 (seki, "stone"), linking the word to the preservation of ancient remains as stone.

The English phrase living fossil describes a species alive today that closely resembles forms known from ancient fossils, creating a useful contrast between the two terms.