1. A gender that refers primarily, but not exclusively, to inanimate objects that are neither masculine nor feminine: Since Jane's cat was castrated, it is now considered to be a neuter.

The term neuter can also be applied to a rock, sand, a book, or a television!
2. Etymology: a grammatical gender, "neither masculine nor feminine"; from Latin neuter, literally, "neither one nor the other"; from ne-, "not, no" + uter, "either (of two)"; probably a loan-translation of Greek oudeteros, "neither, neuter". In the 16th century, it had the sense of "taking neither side, being neutral."

1. To take away or withdraw the power or effectiveness of something: The discussion on disarmament between the two countries will neuter the military power on both sides.
2. To remove the testicles or ovaries of an animal: Susan's cat was spayed or neutered so it couldn't have kittens anymore.

The verb "to neuter" is from about 1903, from the adjective, originally in reference to pet cats.