insula

Insula, insulae, f., first declension. Entirely regular, which makes it a good early noun.

The second meaning is the one that catches people out. In the city of Rome an insula was a tall rented tenement block, so called because it stood free on every side with streets around it, like an island in the traffic. A Roman reading insula in a legal or satirical text thinks of noise, fire risk and rent arrears before he thinks of palm trees. The word survived intact into the Romance languages, giving French ile and Spanish isla, and English took insulate, isolate and peninsula, which is paene insula, "almost an island".