noun
A traditional Japanese color name for a muted, grayish blue, originally associated with the color of storage room (納戸) walls or fabrics.
彼女は納戸色の着物を着ていた。
She wore a kimono of a grayish blue color.
鼠色 is a pure gray, whereas 納戸色 has a distinct blue undertone.
Compound of 納戸 (なんど, 'storeroom') and 色 (いろ, 'color'). The name likely comes from the color used for 納戸 interiors or stored goods, though the exact historical derivation is uncertain.