Piobaireachd is ancient, classical bagpiping music. It's not the type of music that you would hear in a pub, or probably tap your foot to. It's the type of music that would make you cry and remember your Scottish ancestors...even if you have no Scottish ancestors, like me. Any lucky traveler who happens upon a piper playing Piobaireachd on a foggy Scottish hillside might think they've died and gone to heaven. Literally. It's very haunting.
Like much of jazz, Piobaireachd is a variation on a musical theme. It starts with a relatively simple melody line (the ground) and then adds new and more complex embellishments and variations with each repetition. The number of repetitions can go as high as 20 in some cases, which makes Piobaireachd pieces quite long, compared to other pipe tunes.
The word Piobaireachd means "piping music" in Scots Gaelic. The Gaelic term preferred by most pipers is Ceòl Mòr, which literally means "big music"...as opposed to Ceòl Beag (little music), which describes most tunes you may have heard played on the pipes. Piobaireachd is kind of a hard word to pronounce. It sounds something like peebrokd, with some fancy back of the throat noises going on.
I grew up as the stepdaughter of a McLeod. The MacCrimmons were hereditary pipers to the chief of Clan McLeod of Dunvegan on the Isle of Skye and were considered to be the preeminent practitioners of Piobaireachd (couldn't resist) in Scotland for many generations. There's even a great children's book all about the beginning of the MacCrimmon line of Pipers to the Chief. When I was young, my stepfather was the director of the Coeur d'Alene Summer School of Piping and Drumming, and Piobaireachd which was sponsored at the time by the Spokane Piobaireachd Society. I spent a part of most of my summers growing up listening to world class pipers and high quality Piobaireachd. I loved it and was marked indelibly by my experiences there.