A corm is a short, vertical, swollen underground stem of a plant that acts as a storage organ for food, typically starches, allowing the plant to survive through unfavorable conditions like winter or drought; essentially, it's a solid, fleshy bulb-like structure that differs from a true bulb by lacking layered scales and being entirely solid tissue inside; common examples of plants that grow from corms include crocus, gladiolus, and freesia.