Hypocotyledon

Part of speech: noun

Definitions

1. The portion of a plant embryo or seedling stem that lies below the seed leaves and above the root
2. The stem region of a young seedling found beneath the cotyledons and connecting them to the primary root
3. A botanical term for the embryonic axis segment situated under the seed leaves, linking them to the radicle

Etymology: Hypocotyledon is a botanical coinage, not an ancient term. It was formed in the 18th or 19th century from Greek elements: "hypo-", meaning "under", and "cotyledon", the seed leaf of a plant embryo. Cotyledon itself comes from Greek "kotylēdōn", a word for a cup-shaped hollow or a plant such as navelwort, whose leaves were thought to resemble cups. Botanists used the Greek prefix to name the part of a seedling stem that lies just beneath the seed leaves, the stretch that connects the shoot to the root. The word therefore describes a position rather than a structure in its own right. Its meaning is simply "below the cotyledons," and it was built the same way many scientific terms were, by joining classical building blocks to describe a new observation. Ancient Greek and Roman writers had no need for it, and the word should not be read as evidence of classical botanical knowledge.