The word "neither" is a conjunction used to indicate that two or more options are not true, not occurring, or not applicable. It typically suggests that both options being discussed are being excluded. For example, in the phrase "neither the cat nor the dog is here," it indicates that both the cat and the dog are not present.
The word "neither" comes from the Old English "Nāðer," which is a combination of "nō," meaning "no," and "þer," meaning "there." Over time, it evolved through Middle English before reaching its modern form.