Loom (A. S. loma), a machine for weaving cloth. The loom is one of the oldest inventions, but among the ancients it was of exceedingly simple construction. That which is used at the present time by the natives of India is probably the most ancient form of the machine. The Indian loom consists of two horizontal rollers of bamboo, from one of which the yarn called the warp is drawn, while the woven fabric is wound upon the other. Each alternate thread is raised by a loop attached to a string connecting with a bar above, which being raised by the weaver moves half of the threads at once, leaving a space between them and the remainder for the passage of the woof, which may be effected by a long needle held in the hand or by a shuttle. The first set of alternate threads being now lowered, and the second set raised, the woof is passed back in the opposite direction, separated from the preceding thread of woof by the crossed threads of the warp; and thus the operation is continued. By means of this rude apparatus the natives of the East have made the finest of woven fabrics; but the great secret of their success lies in the perfect manner in which they spin and prepare their thread.

The looms used by the ancient Egyptians, pictures of which are painted and sculptured upon some of their monuments, are of similar form to those of the Hindoos and Chinese; and the form was not very essentially varied in the looms used by western nations in their development toward modern civilization for several thousand years. The first step toward improvement appears to have been made by John Kay of Bury, England, about 1740, by the application of a fly shuttle; but the most important advance was made by Dr. Cartwright in 1787, who, it is said, without ever having seen a loom, constructed one to work by machine power. (For the construction and use of modern looms, see Weaving.)