Going "long," or taking a "long position," is buying an asset with the expectation that the price will go up.

For example, you go long on bitcoin by buying 1 bitcoin at the price of $8000. If the price goes up, to say $9000, you'd pocket $1,000 in profits.

If however, the price goes down to $7,000 and you decide to sell, you'd loss $1,000.The opposite of going long is going short. Going short is when you enter a trade with the expectation that price will go down, and make profits when it does so.

The vast majority of retail investors only do long trades.