The Great Depression, a severe economic recession in the 1930s

Clinical depression, or major depressive disorder, a clinical term for a state of intense sadness, melancholia or despair that has advanced to the point of being disruptive to an individual's social functioning and/or activities of daily living. Subtypes of clinical depression:

Postnatal depression, depression following childbirth. Also known as 'Postpartum depression' or, usually when less severe, 'maternity blues' or 'baby blues'

Depression (personality), a personality facet in Revised NEO Personality Inventory.

Depression (economics), a more severe economic downturn than a recession

Depression (mood), a common term for a sad or low mood or emotional state, or the loss of pleasure

Depression (meteorology), an area of low atmospheric pressure

Atypical depression, a common long term cyclical form of depression in which the individual can feel enjoyment, eat, and sleep, but there is significant lethargy, a 'leaden' feeling, and a strong response to rejection-related issues

Depression (geology), a sunken landform

Depression (kinesiology), an anatomical term of motion

Psychotic depression, in which clinical depression co-exists with psychotic or delusional perceptions

Melancholic depression, characterized by the inability to find pleasure in positive things combined with physical agitation, insomnia, or decreased appetite

Depression (physiology), a lowering, in particular a reduction in a biological variable or the function of an organ, antonym of elevation