What four-letter English word is a name for a public open-air swimming pool?

A lido is a name for a public outdoor swimming pool, typically used in British English. The term also describes parts of a beach where people can swim or participate in water sports.

The word comes from the Italian word for 'beach', which features in the names of coastal towns, such as Lido di Venezia. It is thought the term was brought to England by tourists in the 19th century.

An example of a British lido is Saltdean Lido in the city of Brighton and Hove. It was built in 1938 by the architect Richard Jones. The Art Deco design has been described by 'The Daily Telegraph' as "particularly glorious, with its elegant, curved lines – rather like a stately ocean liner."

Other examples of lidos include Tinside Lido in Plymouth, Stonehaven Lido in Aberdeen, and Parliament Hill Lido in Hampstead, London.