洋底地殼

oceanic crust (geology)

ocean / vast / foreign / silver dollar or coin

ocean floor / bottom of the ocean

(equivalent to 的 as possessive particle)

background / bottom / base / end (of the month, year etc) / remnants / (math.) radix / base

-ly / structural particle: used before a verb or adjective, linking it to preceding modifying adverbial adjunct

earth / ground / field / place / land / CL:片[pian4]

the Earth's crust

shell / carapace / crust (earth's crust etc) / also pr. [ke2]