yes,
Shannon is correct. A one lift max is the heaviest weight you can lift with good form 1x and some measure it exactly that way, however, the risk of injury is high and to avoid potential injury it can also be calculated based on a set with more reps. This would give you a weight that is a close approximation to your 1 rep max.
A 1 rep max is as others have pointed out one indication of your strength and you use that value to figure out how much weight to use in your workouts typically calculated as a percentage of your 1 rep max..