If you purchase something and sell it for a profit you’ve created a GAIN.
The opposite creates a LOSS.
A GAIN outside of a retirement account is going to be taxed.
Depending upon your income level and how long you owned it before you sold it determines whether or not the gain is short-term or long-term.
it was sold within a year of purchase for a profit.
it was sold after you owned it for more than a year for profit.
For some people, long-term capital gains are tax-free. Others are subject to a preferential rate. Short-term gains are taxed as income.