hog, Heavy, fat-producing domesticated pig developed in the U.S. in the late 19th and early 20th century. As the growing use of cheaper vegetable oils decreased the importance of lard as a source of fat, meatpackers sought hogs yielding more lean meat and less fat, and breeders (mostly European) began crossbreeding programs to obtain lean meat and vigorous animals. Today the term hog is often used for any pig weighing more than 120 lbs (54 kg).