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the locomotory and feeding organ provided with cilia found in the larval stage called the veliger or "velum-bearing" stage of bivalves, such as mussels and oysters; also a delicate membrane found on certain Protists.

the circular membrane round the cap of a sea jelly or medusa of class Hydrozoa

the veil-like membrane of immature mushrooms extending from the margin of the cap to the stem and torn by growth, revealing the gills of a mature sporophore; in a mature mushroom, the remains of the velum may form an annulus or ring around the stem, familiar from common button mushrooms and sometimes on the margin of the cap.

the soft palate behind the hard palate

Velum is also a common misspelling of vellum, pigs skin with which books were once covered. Today, Leatherette, leather, cloth or paper are more commonly used.