- Only for humans

1 [noncount] : a pattern on cloth of stripes with different widths that cross each other to form squares — often used before another noun, a plaid pattern, a plaid shirt, 2 plaids [plural] US : clothes with plaid patterns, She likes to wear plaids. 3 [count] : a woolen cloth with a plaid pattern that is worn over the shoulder as part of the Scottish national costume