Entente refers to the understanding or agreement between Britain, France, and Russia (later replaced by the United States) before and during World War One. It was not a formal alliance but an informal cooperation.
Related terms
Triple Entente: The pre-war understanding between Britain, France, and Russia that was strengthened over time.
Western Front: The line of trenches stretching from the English Channel to Switzerland where most of the fighting occurred in World War One.
Eastern Front: The region where Germany and Austria-Hungary fought against Russia during World War One.