fenes-tella

from The Century Dictionary.

• noun [capitalized] A genus of pyreno-mycetous fungi having the perithecia arranged in more or less definite groups beneath the surface of the bark of the host.
• noun A small window.
• noun In Roman Catholic churches, a niche on the south side of an altar, containing the piscina, and frequently also the credence.
• noun [capitalized]
• noun In zoöl.: The typical genus of the family Fenestellidœ.
• noun A genus of bivalve mollusks.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Arch.) Any small windowlike opening or recess, esp. one to show the relics within an altar, or the like.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun oval or circular opening; to allow light into a dome or vault