The term 'A CAP ON PUT' can be solved by the word 'LIMIT'. This term is used to describe a restriction or boundary on something. It is often used in the context of setting a maximum or minimum amount of something, such as a LIMIT on spending or a LIMIT on the number of people allowed in a certain area. It can also be used to refer to a restriction on an action or behavior, such as a LIMIT on how much noise one can make or a LIMIT on how late someone can stay out.