To make someone feel sad or dejected. The gloomy weather tends to depress me.
To press down on something, especially a button or key. Depress the brake pedal to slow down the car.
To reduce the level or amount of something, such as prices or wages. The new policy is likely to depress housing prices.
To decrease or inhibit the activity or function of (a bodily organ, system, or chemical process). Certain anesthetics can depress the respiratory center in the brain.