What's the difference between depression and feeling depressed in terms of symptoms?

depression is a mental disease that lasts for years and can be treated but not cured

symptoms: feelings of emptiness, numbness, worthlessness, change in eating and sleeping habits, thoughts of hurting yourself, loss of enjoyment of things you use to like,fatigue, physical pain(headaches and stuff) digestion problems, pessimism, inappropriate guilt, difficulty concentrating, suicidal thoughts (may or may not be seriously considering them), some other thing that basically means lacking emotions but i forgot what it was called.

there are many more and people dont get every single one of them.

because depression can simply look like ur just very sad to other people, that has become another meaning of it. if ur just very sad for a few days ur not depressed (as a disease) but you are as a mood if that makes sense.

depression is usally called major depressive disorder or clinical depression or something else to tell the differance between it and the mood

In the fields of psychology and psychiatry, the terms depression or depressed refer to both expected and pathologically chronic or severe levels of sadness, perceived helplessness, disinterest, and other related emotions and behaviours. The Diagnostic and Statistical Manual of Mental Disorders (DSM) states that a depressed mood is often reported as being: "depressed, sad, hopeless, discouraged, or 'down in the dumps'." In traditional colloquy, "depressed" is often synonymous with "sad," but both clinical and non-clinical depression can also refer to a conglomeration of more than one feeling. Such a mixture can include (but is not limited to) anger, fear, anxiety, despair, guilt, apathy, and/or grief, in addition to what many people would describe as typical "sadness."

There are some good days when you have depression, but usually it will be classified as Depression if "you are feeling the symptoms, more days than not, for 3 weeks".

I would say the best way to distinguish Major Depressive Disorder from just feeling down, aside from the period of time, would be the physical symptoms.
Those include:
- sleeping more than usual, or experiencing insomnia
- gaining or loosing a significant amount of weight without trying
- having trouble concentrating
- aches, such as stomach or back aches.

If you are just feeling blue, it's significantly easier to cheer up when around good friends and such. With depression, it usually takes a lot of effort to feel happy, and things that you enjoy just aren't interesting anymore.

you can be depressed by a sad event in your life...most people are after major disappointments. its depression when it isn't affected by events, good OR bad. to be considered depression it does have to be for at least 2 weeks or more.

I think depression is longer in terms of months. Being depressed is having bad days, having depression is NEVER having a good day but in more than just a few weeks. I'm sure there's more, but that's what I have off the top of my head :)

Depression lasts longer then the depression in terms of symptoms.