the.com/ground squirrel

means A small burrowing rodent in the squirrel family that lives in underground tunnels rather than trees, often seen standing upright on its hind legs to watch for danger.

from Straightforward compound etymology: 'ground' plus 'squirrel.' The word 'squirrel' itself traces back through Old French 'esquireul' to Latin 'sciurus,' borrowed from Greek 'skiouros' — literally 'shadow-tail,' a nod to the bushy tail arched over the body for shade. 'Ground' is just the plain Old English word for earth or soil. So the name does exactly what it says: it specifies which kind of shadow-tail you're dealing with — the dirt-dwelling kind, not the tree-dwelling kind.