noun
interlining; padding fabric; foundation cloth
A stiffening or padding material sewn between the outer fabric and lining of clothing, bags, or crafts to give shape and body. Common in tailoring.
襟に芯地を入れると形がきれいになる。
Putting interlining in the collar makes it hold its shape nicely.
このバッグには厚手の芯地が使われている。
A thick padding fabric is used in this bag.
Compound of 芯 (しん, 'core') and 地 (じ, 'cloth, fabric'). The reading しんじ follows standard on'yomi. The alternate spelling 心地 is likely a phonetic substitution (ateji) or historical variant, but the exact derivation is uncertain.