Simply put, this is the number of threads per square inch.
both vertical and horizontal, in a one-inch square of fabric. Hold the sheet up to the light, if you can see through the fabric and make out the actual weave, you’ve got a low thread count on your hands. The higher the thread count (or tc), the softer and more lustrous the fabric, and the more durable and less prone to shrinkage.|
PERCALE: A smooth, flat, closely woven and combed fabric that comes in 100% cotton or 50/50 cotton/poly blends. Finer than muslin, expect TC’s here to range from 180-250.
PIMA or SUPIMA: A high quality cotton whose long fiber staple is somewhat similar to that of Egyptian cotton. The differences are geographical only. Pima is grown in the southwestern part of the U.S. and Egyptian is grown along the Nile River. Supima is made from extra-long staple Pima. The soft hand feel of Pima and Supima make them very desirable in bedding. Expect to find TC’s here from 200-300.
EGYPTIAN COTTON: This is the cotton queen of the Nile. Grown alongside the river, this quintessential cotton owes its superior durability, luster, and silky hand feel to its extra long fiber staple. TC counts range from 200-1000.
SATEEN: a weave construction that has more yarn surface on the face of the cloth than other basic weaves giving a softer hand and more lustrous look.