Origins
Depression means a pressing down, from Latin deprimere, built from de- (down) and premere (to press).βββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββ The word entered English in the 14th century for a physical lowering β a depression in the ground is a place where the surface has been pressed down. The metaphorical extensions to mental health and economics came later, but both preserve the same spatial image of something being pushed below its normal level.
The psychological meaning appeared in the 1660s. Earlier English used melancholia (from Greek, literally black bile) as the primary term for persistent sadness. The gradual shift from melancholia to depression reflected a broader change in medical thinking β away from ancient humoral theory and toward mechanical metaphors drawn from physics. Something was pressing the spirits down, not contaminating them with dark fluid.
The economic meaning first appeared in the 1790s, when business commentators described downturns as depressions of trade. The usage was established well before the crisis of the 1930s. The Great Depression earned its capital letters because of its severity, not because the word was new. After the 1930s, economists began avoiding depression for milder downturns, adopting recession as a softer alternative.
Latin Roots
Latin premere generated a vast family through its prefixed forms. Compress (to press together), express (to press out), impress (to press into), suppress (to press under), and repress (to press back) are all direct descendants. Print (from French printe, an impression) and pregnant (before giving birth, literally before being produced) connect to the same root through more distant channels.
In meteorology, a depression is a region of low atmospheric pressure β air pressed down relative to surrounding areas. The geographical, psychological, economic, and meteorological uses all converge on the same metaphor: something below where it should be, pressed down by forces acting upon it.