Definition of decrease

• n. - To grow less, -- opposed to increase; to be diminished gradually, in size, degree, number, duration, etc., or in strength, quality, or excellence; as, they days decrease in length from June to December.
• v. t. - To cause to grow less; to diminish gradually; as, extravagance decreases one's means.
• v. - A becoming less; gradual diminution; decay; as, a decrease of revenue or of strength.
• v. - The wane of the moon.