adjective

1. (used only with indefinite or interrogative pronouns) Other; in addition to previously mentioned items.

   “The instructor is busy. Can anyone else help me?”

adverb

1. (follows interrogative adverbs) Otherwise, if not.

   “How else (=in what other way) can it be done?”

Synonyms: otherwise

conjunction

1. For otherwise; or else.

   “Then the Wronskian of f and g must be nonzero, else they could not be linearly independent.”