Actinomorphy

Part of speech: noun

Definitions

1. The quality of a flower whose parts can be divided into identical halves along more than one plane, giving it a star-like shape
2. Regular radial symmetry in a bloom, where any vertical cut through its center yields two matching mirror halves
3. The condition of having flower parts arranged so that the blossom is symmetrical around its central axis in several directions

Etymology: Actinomorphy is a botanical and zoological term for radial symmetry, the condition in which a flower, starfish or similar body can be cut into matching halves along more than one plane. The word is built from two Greek elements. "Aktis" (genitive "aktinos") meant "ray" or "beam", the same root that gives "actinium" and "actinic", while "morphē" meant "form" or "shape", the source of "morphology". Put together, the name describes a form organised around rays radiating from a central point. The word's first half, "actino-", shows up in many scientific coinages, usually where something radiates or emits rays. The second half, "-morphy", takes the "morph" root and turns it into a noun for a state of having a certain form. Scientists in the nineteenth and twentieth centuries assembled such terms from classical parts to name structures that ancient Greeks never described, so the word is a modern technical coinage rather than something the Greeks themselves used.

Synonyms: radial symmetry

Antonyms: zygomorphy