Definition of "testudo"

(Ancient Rome, military, historical) 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.  examples

(anatomy) The fornix.  examples

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

(pathology) An encysted tumour.