What does "hornpipe" mean?

Hornpipe: (a) An instrument of music formerly popular in Wales, consisting of a wooden pipe, with holes at intervals. It was so called because the bell at the open end was sometimes made of horn. (b) A lively tune played on a hornpipe, for dancing; a tune adapted for such playing. Many a hornpipe he tuned to his Phyllis. Sir W. Raleigh. (c) A dance performed, usually by one person, to such a tune, and popular among sailors.