CAIs

Cais is a Portuguese noun meaning quay, dock, or waterfront, referring to a raised platform or edge along a harbor, river, or seafront used for loading, unloading, and mooring vessels. In broader usage, cais can describe waterfront streets or promenades that run beside a harbor or river.

In civil engineering and urban planning, a cais is a structure designed to accommodate ships and boats. Typical features include a solid edge for mooring, access ramps, and protective revetments. Historical cais are often built from stone or masonry, while modern versions may use concrete and steel.

The term also appears in geographic names, especially in Portugal and Brazil, to denote waterfront districts or ports. Notable examples include Cais do Sodré, a riverside neighborhood and major transit interchange in Lisbon, and Cais das Colunas, a historic quay in central Lisbon. These names reflect the historical role of the waterfront as a center for commerce, transport, and social activity.

Cais is also used as a surname in Portuguese-speaking countries. As a family name, it appears across various contexts and professions, reflecting the common linguistic practice of deriving surnames from places or occupations tied to the waterfront.