Definitions
1.nounA shelter formed by a body of troops by holding their shields or targets close together over their heads.
2.nounA shelter of similar shape for miners, etc.
3.nounA kind of lyre; so called in allusion to the lyre of Mercury, fabled to have been made of the shell of a tortoise.
4.nounAn encysted tumour.
5.nounThe fornix.