I've been hearing people saying "markets are crashing" or "we are in the bear market territory" a lot. What does that mean?

It's just a phase of negative returns of capital appreciation, possibly overdue given the

long, long, long contrary bull market over more than 10 years before.

Even now some experts say that the worth (price valuation) of U.S. companies still

is higher than the average, with 'retun to the average' an ultra-longterm hypothesis.

on my (still) unchanged private view of investing You may want to read more here:

https://seedly.sg/questions/what-is-your-genera...

A bull strikes with its horns upwards while a bear strikes with its paws downwards.

So a bull market would mean that prices are going up whereas a bear market would mean that prices are going down.

When talking about market sentiment, feeling 'bullish' means the investor believe prices will go up in the long run whereas feeling 'bearish' means they believe prices will fall.