Heather is a type of small, flowering plant found in many parts of the world. It has small, colorful flowers that usually grow in pink, purple, or white clusters. Full definition
This suiting fabric in heather grey is a luxurious blend of lightweight cashmere and smooth silk. (ar.tissura.com)
I somehow acquired a pair of heathered grey sweatpants and a sweatshirt that are the EXACT same color and my boyfriend refers to me as «the grey blob» when I wear them (which is all the time when it's cold)! (un-fancy.com)
One of which is this sweater in heather gray. (looplooks.net)