late 14c., of grammatical gender, "neither masculine nor feminine," from L. neuter, lit. "neither one nor the other," from ne- "not, no" (see un-) + uter "either (of two);" probably a loan-translation of Gk. oudeteros "neither, neuter." In 16c., it had the sense of "taking neither side, neutral." The verb is 1903, from the adj., originally in ref. to pet cats.