"To begin at the beginning: what is an idiom? Perhaps the shortest meaningful answer to that question would be 'a phrase that behaves like a word'. We are used to thinking of words as the lowest common denominators of meaning. But then consider, for example, the phrase a pig in a poke. What can we make of that if we try to interpret it word by word? Even if we know what a poke is (or was), which most people probably do not, it would make very little sense. Or take the phrase haul someone over the coals. Its literal meaning would, in virtually any context, be totally inappropriate. Understanding each individual word does not get us very close to the meaning of the phrase; we have to interpret the phrase as a whole, almost as if it was a single word in its own right. It is phrases like these that are known as 'idioms' and they form the subject matter of this dictionary"--