fenestra
fe.nes.tra \fi-'nes-tr*\ \-.tre-, -.tri-\ \-tr*l\ n or fe.nes.trae [NL, fr. L, window] pl 1: a small opening; esp : either of two apertures in the bone betwe en the middle and inner ear 2: an opening cut in bone 3: a transparent spot - fe.nes.tral aj