It's a complex issue, which perhaps could be phrased as

Highland Dress is mere clothing v Highland Dress is a costume

As with many such debates the truth is probably a grey area somewhere between the extremes.

In 19th century and well into the 20th Highland Dress is often referred to, in books on the subject and by the firms producing it, "costume".



Part of this use of the word "costume" could be semantic shift, a continuous process in language. It seems clear that "costume" meant something different to a Victorian Scot than it does to a modern American.

It's possible that today the term "costume" has different shades of meaning in Britain and in the USA. Certainly the term "fancy dress" means quite different things in the two countries.

All of these semantic issues aside, for the people in my community, that of competition Pipe Bands, Highland Dress is certainly not ordinary clothing but a specialised occupational form of dress, much like the orchestral musician's tuxedo or the mariachi musician's costume.