Congratulations! This is a correlative conjunction.
Correlative conjunctions work only in pairs:
- either/or
- neither/nor
- not only/but also
- whether/or
Remember that when either and neither are used without or and/or nor they act as adjectives or pronouns.
- Either movie seems to be a good choice. (adjective)
- Either seems like a good choice to me. (pronoun)
- Neither book was good. (adjective)
- Neither was good. (pronoun)