A jig is a lively, festive kind of dance. When you do a jig, you spend a lot of time hopping, kicking, and shuffling your feet.
The jig is mainly associated with Ireland and Scotland, and it plays a big role in both traditional Irish dancing and Scottish country dancing. The jig also influenced 20th century African American tap and soft-shoe dance styles. You can also call the type of tune that's played to accompany the dance a jig. The source of jig is most likely the Middle French giguer, "to dance" or "to jump."