What does "depress" mean?

Additional senses

1. 2.To cast a gloom upon; to sadden; as, his spirits were depressed.
2. 3.To lessen the activity of; to make dull; embarrass, as trade, commerce, etc.
3. 4.To lessen in price; to cause to decline in value; to cheapen; to depreciate.
4. 5.(Math.) To reduce (an equation) in a lower degree. To depress the pole (Naut.), to cause the sidereal pole to appear lower or nearer the horizon, as by sailing toward the equator.
5. 6.Having the middle lower than the border; concave. [Obs.] If the seal be depress or hollow. Hammond.