velum

1. A thin membrane resembling a veil or curtain.

   The soft palate.

2. A thin membrane partially covering the cluster of sporangia near the leaf base in quillworts and their extinct relatives.

3. A veil-like membrane of immature mushrooms extending from the margin of the cap to the stem and is torn by growth, to reveal the gills.

4. A locomotory and feeding organ provided with cilia found in the larval stage of bivalves.

5. An annular membrane, typically bordering a cavity, especially in certain molluscs, medusae, and other invertebrates.

6. A delicate membrane found on certain protists.

7. An accessory cloud resembling a veil extending over a large distance; normally associated with cumulus and cumulonimbus.

8. A thin coating or film of mucus or phlegm.

regular