de·crease 
(dĭ-krēs)
(dĭ-krēs)intr. & tr.v. de·creased, de·creas·ing, de·creas·es
To become or cause to become less or smaller, as in number, amount, or intensity.
n. (dēkrēs′)
1. The act or process of decreasing.
2. The amount by which something decreases.
[Middle English decresen, from Old French decreistre, decreiss-, from Latin dēcrēscere : dē-, de- + crēscere, to grow; see ker-2 in the Appendix of Indo-European roots.]
de·creasing·ly adv.
Synonyms: decrease, lessen, reduce, dwindle, abate, diminish, subside
These verbs mean to become smaller or less or to cause something to become smaller or less. Decrease and lessen have the most general application: saw the plane descend as its speed decreased; vowed to decrease government spending; an appetite that lessened as the disease progressed; restrictions aimed at lessening the environmental impact of off-road vehicles.
Reduce often emphasizes bringing down in size, degree, or intensity: reduced the heat once the mixture reached a boil; workers who refused to reduce their wage demands.
Dwindle suggests decreasing bit by bit to a vanishing point: savings that dwindled away in retirement.
Abate stresses a decrease in amount or intensity and suggests a reduction of excess: a blustery wind that abated toward evening; increased the dosage in an effort to abate the pain.
Diminish stresses the idea of loss or depletion: a breeze that arose as daylight diminished; a scandal that diminished the administration's authority.
Subside implies a falling away to a more normal level or state: floodwaters that did not subside until days after the storm passed; anger that subsided with understanding.
These verbs mean to become smaller or less or to cause something to become smaller or less. Decrease and lessen have the most general application: saw the plane descend as its speed decreased; vowed to decrease government spending; an appetite that lessened as the disease progressed; restrictions aimed at lessening the environmental impact of off-road vehicles.
Reduce often emphasizes bringing down in size, degree, or intensity: reduced the heat once the mixture reached a boil; workers who refused to reduce their wage demands.
Dwindle suggests decreasing bit by bit to a vanishing point: savings that dwindled away in retirement.
Abate stresses a decrease in amount or intensity and suggests a reduction of excess: a blustery wind that abated toward evening; increased the dosage in an effort to abate the pain.
Diminish stresses the idea of loss or depletion: a breeze that arose as daylight diminished; a scandal that diminished the administration's authority.
Subside implies a falling away to a more normal level or state: floodwaters that did not subside until days after the storm passed; anger that subsided with understanding.