bathy-

Also batho-.

Depth.

Greek bathus, deep.

A bathysphere is a manned spherical chamber for deep-sea observation; a bathymeter measures the depth of water in seas or lakes; bathypelagic (Greek pelagios, of the sea) refers to organisms inhabiting the deep sea. Words in batho‑ derive from the related Greek bathos, depth: bathochromic (Greek khrōma, colour), relating to or denoting a shift of the absorption spectrum of a compound towards longer wavelengths (figuratively, deeper ones); batholith (Greek lithos, stone), a very large igneous intrusion extending to an unknown depth in the earth's crust.