Any music or discussion of music with an Irish traditional or folk basis, from old Irish harp music to Ceoltóirí Chualann and beyond is welcome. That includes traditional dance tunes, folk music, folk revival, Céilidh bands, modern art music, sean nós songs etc. (even Celt punk, if you want), in Irish or English.
Jig: There are three types of jig: the single jig (6/8 w/quaver movement), double jig (6/8 w/crotchet-quaver movement) & slip-jig (9/8 w/quaver movement)
Reel: Written in 4/4, but played in 2/2 with 2 beats per bar
Hornpipe: Most modern hornpipes are in 4/4, but is more complicated with dotted rhythms and triplets frequently used
Slide: Played in 12/8 time, it is closely related to the jig
Polka: A very fast tune type in 2/4; more generic dance tune, but still played often in Irish traditional music
Highland: Related to Scottish highland flings, highlands are largely played in Co. Donegal. It is played with a dotted rhythm Alla Breve.
Sean Nós: A traditional style of singing consisting of one voice unaccompanied using plenty of ornamentation
Sliabh Luachra: An area in Munster containing parts of Cork, Kerry and Limerick which developed its own distinct playing style as distinct as Sligo, East Galway/Clare, Donegal
Ceoltóirí Chualann: A band formed by Seán Ó Riada, but the name now describes the style also. The music was orchestrated and styled after European art music, introducing features never seen in Irish music before (such as counterpoint). This is the style of music played by bands like The Chieftains.