Sex"u*al (?), a. [L. sexualis,
fr. sexus sex: cf. F. sexuel.] Of or pertaining to
sex, or the sexes; distinguishing sex; peculiar to the distinction and
office of male or female; relating to the distinctive genital organs
of the sexes; proceeding from, or based upon, sex; as, sexual
characteristics; sexual intercourse, connection, or commerce;
sexual desire; sexual diseases; sexual
Sexual dimorphism (Biol.), the
condition of having one of the sexes existing in two forms, or
varieties, differing in color, size, etc., as in many species of
butterflies which have two kinds of females. -- Sexual
method (Bot.), a method of classification
proposed by Linnæus, founded mainly on difference in number and
position of the stamens and pistils of plants. -- Sexual
selection (Biol.), the selective preference of
one sex for certain characteristics in the other, such as bright
colors, musical notes, etc.; also, the selection which results from
certain individuals of one sex having more opportunities of pairing
with the other sex, on account of greater activity, strength, courage,
etc.; applied likewise to that kind of evolution which results from
such sexual preferences. Darwin.
In these cases, therefore, natural selection seems to
have acted independently of sexual selection.
A. R. Wallace.