The term 'ACT ADDITION' is a crossword solution that consists of three letters: IVE. This term is an abbreviation for the phrase 'ACT of ADDITION, ' which is a legal term used to describe a situation in which a person or entity adds something to an existing contract or agreement. This ADDITION can be in the form of a clause, amendment, or other modification. The ACT of ADDITION is often used to modify existing contracts or agreements in order to make them more suitable for the current situation.