Lace
Lace yarn is the thinnest yarn used in knitting. It is very light and airy, and is often used for “finest” projects that are not subject to heavy wear, such as shawls and scarves.
Lace yarn is also often knitted in combination with another yarn. For example, lace-strength silk mohair yarns are often combined with merino wool yarns, which gives the final result a touch of sophisticated fluffiness.