Noah Webster's New International Dictionary of the English Language

1. (n.) One who accompanies or is in company with another for a longer or shorter period, either from choice or casually; one who is much in the company of, or is associated with, another or others; an associate; a comrade; a consort; a partner.

2. (n.) A knight of the lowest rank in certain orders; as, a companion of the Bath.

3. (n.) A fellow; -- in contempt.

4. (n.) A skylight on an upper deck with frames and sashes of various shapes, to admit light to a cabin or lower deck.

5. (n.) A wooden hood or penthouse covering the companion way; a companion hatch.

6. (v. t.) To be a companion to; to attend on; to accompany.

7. (v. t.) To qualify as a companion; to make equal.