Corms are storage structures of some plants. They are swollen underground stems with dry-scale leaves covering them. In favorable conditions, they grow in size and can remain dormant in adverse conditions. Corms can be cut into pieces and each piece planted to produce a new plant. The daughter corms that grow on mature corms are called cormels. Cormels can also be separated and planted.

Corms are different from bulbs. When cut open, they are solid and not layered like bulbs. Gladiolas and crocuses are great examples of plants with corms.