Perigynium \Per`i*gyn"i*um\, n.; pl. Perigynia. [NL. See Perigynous.]

(Bot.) Some unusual appendage about the pistil, as the bottle-shaped body in the sedges, and the bristles or scales in some other genera of the Sedge family, or Cyperace[ae].

Source: Webster's Revised Unabridged Dictionary (1913)