Mathematics. (of a function) having the property that for any two points in the domain such that one is larger than the other, the image of the larger point is less than or equal to the image of the smaller point; nonincreasing. Compare increasing (def 2).
to diminish or lessen in extent, quantity, strength, power, etc.: During the ten-day march across the desert their supply of water decreased rapidly.
to make less; cause to diminish: to decrease one's work load.
the act or process of decreasing; condition of being decreased; gradual reduction: a decrease in sales; a decrease in intensity.