An idiom is a common expression or phrase that has a figurative, or sometimes literal, meaning. It is different from other types of expressions because its meaning cannot be deduced solely from the meanings of its individual words. Instead, it conveys a specific concept or idea that is unique to the language and culture in which it is used. Idioms are often metaphorical, using imagery and exaggeration to convey their message. They can also vary widely between different languages and cultures.