Plaid, the American word for tartan (and an incorrect usage of the word, if you’re going to be a nudge about it), is a colorful pattern of interlocking stripes running in the warp and weft of a fabric. But while tartan was for a time outlawed in Scotland by the British government and today may represent a Scottish person’s “clan”, plaid is mostly just a handsome pattern for a hiking shirt or a wool tie. Or a dog bed. Or a pocket square. Perhaps even a suit. You’ll find it on the golf course in Georgia and in a dive bar in Portland. Wear it right — in moderation — and you’ll look dapper. Go overboard and you’ll look like a dope. Do as we say, not as we do.