opium den
A place where opium is smoked, often associated with historical or literary contexts.
In 19th-century Shanghai, there were many opium dens.
Mixed katakana-kanji spelling; アヘン is a common katakana representation of opium.
Compound of 阿片 (ahen, 'opium') + 窟 (kutsu, 'cave, den'). The exact historical derivation is uncertain, but the term refers to a den where opium is consumed.