Buying shares of stock is just another form of gambling disguised as investing.
If you are using a short term strategy like day trading then you are not investing anything . Some people buy stock for long term but sometimes people buy it for short term
Yes you are generally correct. There is a big difference between investing and trading. Trading is generaly short term, and sometimes you can go short and make money when something goes down.
Investing is usually holding stocks for a few years.