Zygomorph

Part of speech: noun

Definitions

1. Describing a biological structure that exhibits bilateral symmetry such that it can be divided into mirror-image halves along only one plane; typically referring to flowers or organisms with this distinct symmetrical arrangement; characterized by a single plane of symmetry rather than multiple or radial
2. Pertaining to entities, especially botanical specimens, that display symmetry limited to one specific axis resulting in two equal halves; commonly applied to floral forms that have a distinct line of reflection producing symmetry; indicating an asymmetric form when compared to radial symmetry
3. Relating to plants or animals having a shape that allows symmetry across only a single vertical plane, especially seen in certain flowers; this form creates two mirror-image portions but lacks symmetry in other directions; denoting a condition opposed to radial symmetry where multiple planes exist

Etymology: Zygomorph is a technical coinage, built in the 19th century from Greek roots rather than inherited from antiquity. The first element comes from Greek "zygon," meaning "yoke" or "pair," the same root that gives English "zygote," a cell formed by the joining of two gametes. The second element is Greek "morphē," meaning "form" or "shape," which appears in words like "amorphous" and "metamorphosis." Put together, the term literally means something like "yoked form," a shape whose two halves are joined as a matched pair. The word is used mainly in botany and zoology. A zygomorphic flower, such as a snapdragon or a pea blossom, can be cut in only one way to produce two mirror-image halves. This contrasts with actinomorphic, or radially symmetrical, flowers like a buttercup, which can be divided into mirror halves along many lines.

Synonyms: bilaterally symmetrical flower, bilateral flower

Antonyms: actinomorph, radially symmetrical flower