one and the other; two together: He met both sisters. Both performances were canceled.
the one as well as the other: Both of us were going to the party.
alike; equally: He is both ready and willing.
the two; two considered together: both dogs were dirty (as pronoun): both are to blame
(coordinating) used preceding words, phrases, or clauses joined by and, used to emphasize that not just one, but also the other of the joined elements is included: both Ellen and Keith enjoyed the play, both new and exciting