testudines

noun, plural tes·tu·di·nes [te-stood-n-eez, –styood-] /tɛˈstud nˌiz, -ˈstyud-/.

(among the ancient Romans) a movable shelter with a strong and usually fireproof arched roof, used for protection of soldiers in siege operations.
a shelter formed by overlapping oblong shields, held by soldiers above their heads.

noun plural -dines (-dɪˌniːz)

a form of shelter used by the ancient Roman Army for protection against attack from above, consisting either of a mobile arched structure or of overlapping shields held by the soldiers over their heads