It is what we call Celtic Music, common term for Irish, Scottish and Canadian Traditional Music. Some of the tunes are adopted into American Traditional Music as well.
So it is instrumental compositions, tunes, historically mostly played for dances and nowadays can be played as concert pieces! Slow tunes though, more like songs played on instrument.
Tunes are usually grouped in the set of same genre, sometimes mixed genres.
And then usually played as the set, not each tune individually. Separate tune composition is common for slow tunes or special music arrangement.