The islands of Great Britain and Ireland are part of an archipelago with a combined area of 315,000 kmē off the west coast of Europe, and the term "Britain and Ireland" is sometimes used, somewhat loosely and incorrectly, to refer to that entire archipelago. This archipelago is often called the "British Isles"; some people believe one should avoid using this term because it could be construed as having the incorrect or politically loaded implication that Ireland is or should be part of the United Kingdom.

More commonly and correctly, the term "Britain and Ireland" is used to refer to the two independent countries within the archipelago, namely the United Kingdom and the Republic of Ireland. This does not include the Isle of Man, the Channel Islands or any of the other smaller islands that form part of the British Isles.

In the context of the Northern Ireland peace process the term "Islands of the North Atlantic" (IONA) has been used as a neutral term to describe these islands.