slate gray unpatterned cloth
A specific fabric term: a plain, unpatterned cloth in a dark gray color, often used in traditional Japanese clothing or accessories.
この着物は鉄無地の生地で仕立てられています。
This kimono is made from slate gray unpatterned cloth.
Compound of 鉄 (tetsu, 'iron') and 無地 (muji, 'plain, unpatterned'), referring to the iron-like gray color and lack of pattern.