What is the meaning of Testudo?

A shelter formed by a body of troops holding their shields or targets close together over their heads.

A shelter of similar shape for miners, etc.

The fornix.

A kind of lyre; so called in allusion to the lyre of Mercury, fabled to have been made of the shell of a tortoise.

An encysted tumour.

tortoise

turtle

tortoise, turtle

tortoise-shell

lyre, lute

covering, shed, shelter

arch, vault

having a big forehead

Source: wiktionary.org