Okay,
I have been on the board for a while now & know which end of a sewing needle is which but one question has been bugging me for ages & I have finally worked up the nerve to ask:

What defines a tartan as a tartan???

I thought it was the squared-off, matching pattern running horizontally and vertically (i cant remember which is the warp & which the weft so if you are feeling benevolent & want to answer that question as well it would be appreciated) BUT having looked at some of the kilts out there (in part those in this thread ) that do not follow such a pattern...

If you coudl please take pity on me and put my simple mind to rest it would be greatly appreciated