I recently had an interesting conversation with my mother-in-law. She was getting ready to purchase a new set of linens for her guest bed and since she knows I love textiles and weaving, she asked for help understanding a couple terms related to bed sheets. Although this isn't exactly knitting-related, I thought you may find it helpful.
OEKO-TEX: A label that certifies that every component of a product, has been rigorously tested against a list of hundreds of toxic chemicals. (Learn more on the Hohenstein Laboratories website)
Percale: refers to a tight, plain weave structure, in an over-under pattern. Percale cotton sheets typically have a crisp hand and feel.
Sateen: refers to a tight weave structure, usually with a four over, one under pattern. Sateen cotton sheets typically have a silky hand and feel.
Thread Count: the total number of vertical (warp) and horizontal (weft) threads per square inch of fabric. Some people believe that a higher thread count means you are getting softer, better quality sheets, but that's not necessarily the case. The staple length of the individual fibers used to spin the threads and the processes used to finish the fabric vary between manufacturers, so it can be difficult to use a thread count number to really compare quality.
There's more to explore in the Learning Library!