The term 'An Eye for an Eye' is a proverb that has been used since ancient times to describe the concept of REVENGE. It suggests that when someone has wronged another, the wronged person should respond in kind. The crossword solution for this term is 'REVENGE', which is a seven-letter word that describes the act of taking REVENGE on someone who has wronged you. This proverb is still widely used today and is often seen as a way to maintain justice and balance in society.