noun
A kimono made of a single layer of fabric, typically worn in summer or as an undergarment.
夏は単衣の着物が涼しくて快適だ。
In summer, an unlined kimono is cool and comfortable.
noun
one kimono; a single kimono
Only with reading たんい
Used when counting or referring to a single kimono. Restricted to the reading たんい.
箪笥に単衣が一枚だけ残っていた。
Only one kimono was left in the chest of drawers.
単 (single) + 衣 (garment), referring to a single-layer kimono. The reading ひとえ is a gikun (meaning-based reading) from 一重 (single layer).