neither

1150–1200; Middle English, equivalent to ne not + either; replacing Middle English nawther, Old English nāwther, nāhwæther ( nā not, no¹ + hwæther which of two; see whether)

As an adjective or pronoun meaning “not either,” neither is usually followed by a singular verb and referred to by a singular personal pronoun: Neither lawyer prepares her own briefs. Neither performs his duties for reward. When neither is followed by a prepositional phrase with a plural object, there has been, ever since the 17th century, a tendency, especially in speech and less formal writing, to use a plural verb and personal pronoun: Neither of the guards were at their stations. In edited writing, however, singular verbs and pronouns are more common in such constructions: Neither of the guards was at his station.
As a correlative conjunction, neither is almost always followed by nor, not or: Neither the liberals nor the conservatives had originally supported the winner. Subjects connected by neither … nor take singular verbs and pronouns when both subjects are singular ( Neither Diane nor Nicole has her own apartment ), plural when both are plural: Neither the Yankees nor the Dodgers got much help from their bull pens that year. Usage guides commonly say that when a singular and a plural subject are joined by these correlative conjunctions, the noun or pronoun nearer the verb should determine the number of the verb: Neither the mayor nor the council members have yielded on the issue. Neither the council members nor the mayor has yielded on the issue. Practice in this matter varies, however, and often the presence of one plural, no matter what its position, results in a plural verb.
In edited writing the construction following neither is parallel to the one following nor : The great days of American political oratory are neither dead nor waning (not neither are dead nor waning ). This sale sacrifices neither quality nor availability (not This sale neither sacrifices quality nor availability ).
Although some usage guides say that neither may introduce a series of no more than two, it often is used to introduce a series of three or more: The head of that department is neither skillful nor well-prepared nor honest. See also either.

See either.