Dictionary.net

• formerly the United Kingdom and all the territories under its control; reached its greatest extent at the end of World War I; "the sun never sets on the British Empire"

2006 - WordNet 3.0
By Princeton University

• formerly the United Kingdom and all the territories under its control; reached its greatest extent at the end of World War I; "the sun never sets on the British Empire"

2011 - English Dictionary Database
By DataStellar Co., Ltd