*velum*

‖n.; pl. Vela [ L., an awning, a veil. See Veil. ] [ 1913 Webster ]

1. (Anat.) A curtain or covering; -- applied to various membranous partitions, especially to the soft palate. See under Palate. [ 1913 Webster ]

2. (Bot.) (a) See Veil, n., 3 (b). (b) A thin membrane surrounding the sporocarps of quillworts Isoetes). [ 1913 Webster ]

3. (Zool.) A veil-like organ or part. Especially: (a) The circular membrane that partially incloses the space beneath the umbrella of hydroid medusae. (b) A delicate funnel-like membrane around the flagellum of certain Infusoria. See Illust. a of Protozoa. [ 1913 Webster ]