Definition
Adding a fixed amount of weight to the bar every session or every week while sets and reps stay the same.
This is the beginner engine: 3 x 5 on the squat, 2.5 kg more every session, 1.25 kg on the press. It works as long as recovery outpaces the load, which for most new lifters is three to nine months.
It ends when the same reps are missed two sessions in a row, form degrades, or the client starts to dread the session. Then reset the weight by 10% and run it again once, and after that move to weekly progression, double progression or a periodized plan.
Small plates matter. A 1.25 kg jump on a 40 kg press is 3%; a 2.5 kg jump is 6%, which is too much too often.