1) Having a fenestra 2) Having windows 
with window-like areas
Having a fenestra. 
• (a.) Having numerous openings; irregularly reticulated; as, fenestrate membranes; fenestrate fronds. • (a.) Having transparent spots, as the wings of certain butterflies.
with small slits or areas thinned so as to be translucent
Having openings or translucent areas. ... (09 Oct 1997) ... 
(fen´әs-trāt) to pierce with one or more openings.
with small slits or areas thinned so as to be translucent
Fe·nes'trate adjective [ Latin fenestratus , past participle of fenestrare to furnish with openings and windows.] 1. Having numerous openings; irregularly reticulated; as, fenestrate membranes; fenestrate fronds. 2. (Zoology) Having transparent spot...
with window-like areas
fenestrate To create one or more openings in; for example, a tissue.