Traditionally, a sea shanty was a song sung by sailors as they worked on board ships. Their purpose was partly to maintain the rhythm of certain tasks, and partly to alleviate boredom. Often the shanties were call and response songs, where one sailor (known as the shantyman) would sing a line and the other sailors would then respond in unison.
Two well-known sea shanties are What Shall We Do with the Drunken Sailor and Blow the Man Down.
A jig is the name given both to a kind of dance and to the music for that dance. (see also: bookmark, p.59)
Originally in 2/4 time, jigs are now composed in a variety of time signatures.
Two well-known jigs are The Irish Washerwoman and Saddle the Pony.