Some common expressions include "a piece of cake" to describe something very easy, "hit the nail on the head," which refers to getting an idea exactly right, and "spill the beans" to reveal a secret. "When pigs fly" indicates something impossible, and "break a leg" is a good luck wish.
Idioms are phrases or sentences that add impact, variety and flavor to spoken and written language with the help of imagery. Like metaphors, the literal meaning of idioms usually differs from their figurative meaning. In a few words, they express complex ideas. For example, the idiom "costs an arm and a leg" refers to something extremely expensive.
Idioms originate from sources such as scriptures, folktales, archaic language, well-known literature, professions and daily life. For instance, the idiom "feeling under the weather" traces its roots to the practice of seasick sailors or passengers going under the deck of a ship to recover. The idiom "to cry wolf" or raise a false alarm comes from the story "The Boy Who Cried Wolf," one of Aesop's fables.
Native speakers know and use several idioms with natural ease, such as "raining cats and dogs" and "a blessing in disguise." Non-native speakers can learn the meanings of common idioms and practice using them in the right context by referring to lists of popular expressions. Idioms appear in alphabetical order in most lists to enable easy reference. In addition, reading good literature along with articles in newspapers and magazines encourages awareness of popular idioms and expressions.