noun
Refers to a pocket sewn on the inside of a garment, such as a jacket or coat. The word is somewhat dated; modern Japanese often uses 内ポケット (uchi poketto) instead.
祖父のコートのうちかくしに古い手紙が入っていた。
There was an old letter in the inside pocket of my grandfather's coat.
The modern, more common term for 'inside pocket'. 内衣嚢 (うちかくし) is an older, rarely used word.
Compound of 内 (uchi, 'inside') and 隠し (kakushi, 'hiding'), literally 'inside hiding place'. The kanji 嚢 is a rare character meaning 'bag' or 'pouch', possibly used here as ateji or a variant. The exact origin of the spelling is uncertain.