fleece, mat of wool formed by shearing a sheep in one continuous operation. The average fleece weighs from 5 to 10 lb (2.3-4.5 kg); in highbred wool sheep such as the American Merinos a ram's fleece may reach 30 lb (13.6 kg). The weight lost in cleansing the fleece of grease before sorting the wool is called shrinkage. On large sheep ranches hand shearing, once a competition skill, has largely been replaced by machine shearing. In heraldry a fleece is a whole, stuffed ram's fleece, complete with head and feet, suspended by a band around its middle. See also Golden Fleece and sheep.

Golden Fleece, in Greek mythology, the magic fleece of the winged ram that saved Phrixus and Helle, the children of Nephele and Athamas, from the jealousy of Ino, Athamas' second wife. The ram flew to Colchis, but Helle fell into the sea, which was thereafter known as the Hellespont. Phrixus arrived safely, sacrificed the ram, and hung its fleece in a wood guarded by a dragon. The ram became the constellation Aries. Phrixus married a daughter of King Aeëtes of Colchis and begot Argus and three other sons. The quest of Jason and the Argonauts was for this fleece.