Velum \Ve"lum\, n.; pl. Vela. [L., an awning, a veil. See Veil.]

1. (Anat.) Curtain or covering; -- applied to various membranous partitions, especially to the soft palate. See under Palate.

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

3. (Zo["o]l.) A veil-like organ or part. Especially:
   (a) The circular membrane that partially incloses the space beneath the umbrella of hydroid medus[ae].
   (b) A delicate funnel-like membrane around the flagellum of certain Infusoria. See Illust. a of Protozoa.

Source: Webster's Revised Unabridged Dictionary (1913)