MUG (Male Un-bifurcated Garment) is a term coined by the Utilikilts crowd.
The UK is not, and does not pretend to be related to the Celtic Kilt, Cilt.
Because the intent was to develop a totally new type of garment it was thought a new term should be invented also.

My choice for a term to describe the style of Kilt I manufacture is "Contemporary Kilt".

For high waisted, buckled, Tartan kilts I use the wording "Traditional", with a differentation between "Tank" for an 8yd. handsewn, and "Casual" for a less than 8yd and/or machine sewn.