originally indicated a city block, most often bounded by four streets, on which a house or tenement was built. In later usages it came to designate the apartment building itself. Cf. domus and villae.

In Roman architecture, insulae (singular insula) were large apartment buildings where the lower and middle classes of Romans (the plebs) dwelled. The floor at ground level was used for tavernas, shops and businesses with living space on the higher floors.

Latin for "island".