What is the difference between a loom & a power loom? Well, the power loom is mechanized.
A loom is a device used to weave cloth and tapestry.
A power loom is a mechanized loom, and was one of the key developments in the industrialization of weaving during the early Industrial Revolution.
The basic purpose of any loom is to hold the warp threads under tension to facilitate the interweaving of the weft threads. The precise shape of the loom and its mechanics may vary, but the basic function is the same.
The first ideas for an automatic loom were developed in 1678 by M. de Gennes in Paris and by Vaucanson in 1745, but these designs were never developed and were forgotten. In 1785 Edmund Cartwright patented a power loom which used water power to speed up the weaving process, the predecessor to the modern power loom. His ideas were licensed first by Grimshaw of Manchester who built a small steam-powered weaving factory in Manchester in 1790, but the factory burnt down. Cartwright's was not a commercially successful machine; his looms had to be stopped to dress the warp. Over the next decades, Cartwright's ideas were modified into a reliable automatic loom.
These designs preceded John Kay's invention of the flying shuttle and they passed the shuttle through the shed using levers. With the increased speed of weaving, weavers were able to use more thread than spinners could produce.