Collins COBUILD Advanced Learner's English Dictionary - ally

(allied) Frequency: The word is one of the 1500 most common words in English. 1. A country’s ally is another country that has an agreement to support it, especially in war. Washington would not take such a step without its allies’ approval... The United States is a close ally of South Korea. ? adversary N-COUNT: with supp 2. The Allies were the armed forces that fought against Germany and Japan in the Second World War. N-PLURAL: the N 3. If you describe someone as your ally, you mean that they help and support you, especially when other people are opposing you. He is a close ally of the Prime Minister... = supporter, friend ? enemy N-COUNT: with supp 4. If you ally yourself with someone or something, you give your support to them. He will have no choice but to ally himself with the new movement. VERB: V pron-refl with n 5. see also allied