the·ca / ˈ[unvoicedthx113;kə / • n. ( pl. thecae / ˈ[unvoicedthx113;ˌsē / ) a receptacle, sheath, or cell enclosing an organ, part, or structure, in particular: ∎ Anatomy the loose sheath enclosing the spinal cord. ∎ Zoology a ...
July 25, 2008; The Oxford American College Dictionary