1831, "pertaining to origins," coined by Carlyle as if from Greek genetikos from genesis "origin" (see genesis). Darwin used it biologically as "resulting from common origin" (1859); modern sense of "pertaining to genetics or genes" is from 1908 (see gene). Related: Genetically. Genetical is attested from 1650s as "pertaining to origins."
in the names of sciences or disciplines (acoustics, aerobics, economics, etc.), a 16c. revival of the classical custom of using the neuter plural of adjectives with Greek -ikos "pertaining to" (see -ic) to mean "matters relevant to" and also as the titles of treatises about them. Subject matters that acquired their English names before c. 1500, however, tend to be singular in form (arithmetic, logic, magic, music, rhetoric). The grammatical number of words in -ics (mathematics is/mathematics are) is a confused question.