"Roll" is not the same as "result"
The word "roll" literally refers to the roll of a die. Take, for example, the Great Weapon Fighting fighting style:
Great Weapon Fighting
When you roll a 1 or 2 on a damage die for an attack you make with a melee weapon that you are wielding with two hands, you can reroll the die and must use the new roll, even if the new roll is a 1 or a 2. The weapon must have the two-handed or versatile property for you to gain this benefit.
The "roll" refers to the actual number shown on the die.
The "result" is a different matter. It is the total value after applying all modifiers. Take, for example, the indomitable might class feature of the barbarian:
Beginning at 18th level, if your total for a Strength check is less
than your Strength score, you can use that score in place of the
For glibness, you can adjust the d20 roll you make to be 15 regardless of what you actually rolled.