1903, in botany, "group of cultivated plants each of which is a transplanted part of one original," from Latinized form of Greek klon "a twig, spray," related to klados "sprout, young branch, offshoot of a plant," possibly from PIE root *kel- (1) "to strike, cut" (see holt). Meaning "person or animal replicated from a single cell of another and genetically identical to it" is by 1970 (theoretical), Figurative use, "one who slavishly imitates another," is by 1978.
1959, from clone (n.). Extension to genetic duplication of animals and human beings is from 1970. Related: Cloned; cloning.