silk gauze
A thin, translucent silk fabric with a plain weave, used for summer kimono, linings, or decorative purposes.
Silk gauze is often used for summer kimono.
This summer kimono is tailored from silk gauze.
紗 and 絽 are both thin, gauze-like summer silk weaves, but 絽 has a distinct ribbed pattern from alternating plain and gauze weaves while 紗 is uniformly open-weave.
Used because 紗 (a thin, sheer silk fabric) is thin and flat, like other cloth counted with 枚.
The kanji 紗 originally referred to a fine, thin silk fabric in Chinese, and the Japanese reading しゃ is derived from the Chinese pronunciation.