1831, "calculation of life expectancy" (obsolete); see bio- + -metry. Coined by Whewell, popularized 1860s by T.S. Lambert. Later, "application of mathematics to the study of biology" (1894). Related: Biometer, a word used in various senses from the 1830s on; it is attested from 1865 as "life table," calculating the duration of life under given conditions.
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.
<a href="https://www.etymonline.com/word/biometrics">Etymology of biometrics by etymonline</a>
Harper, D. (n.d.). Etymology of biometrics. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/biometrics