|secondary sex characteristic
Any of the physical traits in a sexually mature animal that are specific to one sex but are not directly involved in the act of reproducing. Secondary sex characteristics are thought to have evolved to give an individual an advantage in mating by making the individual more attractive to mates or by allowing the individual to defeat rivals in competition for mates. Some secondary sex characteristics include the facial hair of the human male, the relatively prominent breasts of the human female, the antlers found only in the male of most species of deer, and the colorful plumage of the males of many species of birds. The appearance of secondary sex characteristics is determined by the sex hormones. See more at sexual selection.
A characteristic, such as breast development, voice pitch, or facial hair, that distinguishes the sexes from each other but is not directly concerned with reproduction. The appearance of these characteristics is influenced by hormones.