Word Study
zygomorphic
CIDE DICTIONARY
zygomorphic, a. [Gr. zygo`n a yoke + form.].
Symmetrical bilaterally; -- said of organisms, or parts of organisms, capable of division into two symmetrical halves only in a single plane. [1913 Webster]
OXFORD DICTIONARY
zygomorphic, adj. (also zygomorphous) (of a flower) divisible into similar halves only by one plane of symmetry.
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