pubis n.

1560s, "pubic hair, the pubescence of the genitals; the groin," from Latin pubes "pubescent, arrived at the age of puberty, of ripe years, grown up," also, as a noun, "a sign of puberty" (such as pubic hair), also "young men of the age of puberty" (see pubis). In 19c. also "pubic bone," and earlier "part of either hip bone that forms the front of the pelvis," from Latin os pubis, from pubes "genital area."

In modern slang, monosyllable, it is a familiar shortening of pubic hairs (see pubic).

early 15c., "the coming or attainment of puberty," from Medieval Latin pubescentia, abstract noun from Latin pubescentem (nominative pubescens), present participle of pubescere "grow up; ripen, come to maturity; reach the age of puberty, arrive at puberty," from pubes "adult, full-grown" (see pubis). Biological use in reference to hairiness or soft down is by 1760 of plants, 1826 of insects, etc.