Word Study
sepal
CIDE DICTIONARY
sepal, n. [NL. sepalum, formed in imitation of NL. petalum, petal, to denote one of the divisions of the calyx: cf. F. sépale.].
A leaf or division of the calyx. [1913 Webster]
" When the calyx consists of but one part, it is said to be monosepalous; when of two parts, it is said to be disepalous; when of a variable and indefinite number of parts, it is said to be polysepalous; when of several parts united, it is properly called gamosepalous." [1913 Webster]
OXFORD DICTIONARY
sepal, n. Bot. each of the divisions or leaves of the calyx.
Etymology
F s{eacute}pale, mod.L sepalum, perh. formed as SEPARATE + PETAL
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