The manufacturing of carpet - which can be described as sewing strands of yarn into a backing material - creates thousands of yarn loops. When the carpet is tufted with a high and low loop and left uncut, you have an unlevel, hi-lo or patterned loop. You can also have a patterned loop referred to as a cut loop. This occurs when some of the loops are cut, usually to form a distinctive pattern in the carpet. In some cases you may hear people refer to a distinct coloration in the carpet as a pattern. This is not uncommon but in most cases they are usually referring to a printed pattern or coloration in the yarn.