Make ONE's Day is an expression that is used to describe the act of making someone else feel happy or elated. The term can be broken down into two words, 'MAKE' and 'ONE's day'. To MAKE ONE's day means to do something that will bring joy and happiness to someone else. The crossword solution for this term is ELATE, which is a verb meaning to fill with joy or delight. Therefore, the phrase MAKE ONE's Day can be interpreted as doing something that will bring joy and delight to another person.