Sentence:  Fifteen minutes drive to the Brown Trout was guaranteed to satisfy my appetite because there, as with other clubs and hotel bars, a form of sex <WSD>apartheid</WSD> was practised. The males assembled in the region of the bar and the opposite gender either sat discreetly detached or strayed outside to gossip gaily among themselves. 
Meaning of the word marked with <WSD> tags:  A policy or situation of segregation based on some specified attribute.