a street that is closed at one end 死胡同；死巷 We live in a quiet cul-de-sac. 我们生活在一个安静的小路。 - (figurative)
This particular brand of socialism had entered a cul-de-sac (= could make no further progress). 这个特殊的社会主义品牌已经进入死胡同。
Word Originmid 18th cent. (originally in anatomy): French, literally ‘bottom of a sack’.