Pronunciation: (hī"pu-dûr'mis), [key]
1. Zool.an underlayer of epithelial cells in arthropods and certain other invertebrates that secretes substances for the overlying cuticle or exoskeleton.
2. Bot.a tissue or layer of cells beneath the epidermis. Also,hy'po•derm".
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.