The removal of growing tips (the terminal bud) from stems to promote branching, bushier growth, and often more flowers or fruit.
In plain terms
Pinch or cut off the growing tip of a young plant, and instead of one main stem, you get multiple side branches. This creates a bushier plant with more flowers or fruit-bearing branches. Pinching basil regularly keeps it bushy and productive. Pinching back tomatoes early in the season redirects energy into branching and more fruit production.
Why this matters
Pinching is one of the simplest ways to improve plant form, yields, and flowering. A few seconds of pinching creates significantly better plants.