I. (ˈ)rē+ adjective
1. : directed inward
2. : having its ends closed on itself
reentrant armature winding
II. noun
1. : one that reenters or is reentrant
2.
a. : reentering angle
a reentrant in a fortification
b. : an indentation between two salients in a horizontal plane
a reentrant in a coastline