Idiom is an expression, word, or phrase that has a figurative meaning that is comprehended in regard to a common use of that expression that is separate from the literal meaning or definition of the words of which it is made.
That’s how Wikipedia describes idiom. How many idioms in Russian? Thousands of thousands.
A friend in need is a friend indeed.
We use them every day when we talk with friends or relatives, when we watch TV or read a book, when we listen to a song or send SMS,...