Definition of "Depression" :

noun: pushing down

"Depression of the space bar on the typewriter."

noun: sad feelings of gloom and inadequacy

noun: a sunken or depressed geological formation

noun: angular distance below the horizon (especially of a celestial object)

noun: a concavity in a surface produced by pressing

noun: a state of depression and anhedonia so severe as to require clinical intervention

noun: a mental state characterized by a pessimistic sense of inadequacy and a despondent lack of activity

noun: a long-term economic state characterized by unemployment and low prices and low levels of trade and investment

noun: an air mass of lower pressure; often brings precipitation

noun: a period during the 1930s when there was a worldwide economic depression and mass unemployment