What does Depression, major mean in medical term?

Depression, major means: You may experience severe episodes of depression that are disabling at any time.
(in Medical Dictionary)

What else does Depression, major mean?

Major depression: An illness that affects your ability to sleep, work and eat.
(in Medical Dictionary)

Major depression can manifest as a loss of interest or anorexia, weight loss, overeating, and loss of emotion flat affect. It also includes feelings such as sadness, anxiety, guilt, worthlessness, helplessness, hopelessness, despair, and social withdrawal.
Suicide thoughts, suicide attempt or death-related thoughts. Depression may also include alcohol or drug abuse.
(in Medical Dictionary)