Bouclé yarn is an uneven yarn of two to three plies one of which forms effect loops at intervals around the other core strands; these loops of similar size can range in size from tiny lace to extra bulky.

When spun, bouclé can be created in a single step, using a hollow spindle. It is made by differing the feed rate of the effect yarn with respect to the core yarns, creating a regular or irregular loop effect.