The Collaborative International Dictionary of English v.0.48:

Lamella \La*mel"la\, n.; pl. L. Lamell[ae], E. Lamellas. [L.
   lamella, dim. of lamina plate, leaf, layer: cf. F. lamelle.
   Cf. Lamina, Omelet.]
   A thin plate or scale of anything, as a thin scale growing
   from the petals of certain flowers; or one of the thin plates
   or scales of which certain shells are composed.
   [1913 Webster] Lamellar

WordNet (r) 3.0 (2006):

lamella
    n 1: any of the radiating leaflike spore-producing structures on
         the underside of the cap of a mushroom or similar fungus
         [syn: gill, lamella]
    2: a thin membrane that is one of the calcified layers that form
       bones
    3: thin plate