Introduction Idioms appear in every language, and English has thousands of them. They are often confusing because the meaning of the whole group of words taken together has little, often nothing, to do with the meaning of the words taken one by one. For instance, to “let the cat out of the bag” means to reveal a secreat. In order to understand a language, you must know what the idioms in that language mean. If you try to figure out the meaning of an idiom literally, word by word, you will get befuddled. You have to know its “hidden” meaning.