Attack Roll
The roll to see if an attack hits its target.
To attack, you roll the twenty-sided die. The app adds your attack bonus and compares the total with the target's Armor Class (AC). If it hits, you then roll damage.
In Fantasy RPG
Fantasy RPG: d20 + attack bonus. It hits when the total equals or beats the target's AC. A natural 20 always hits as a critical hit; a natural 1 always misses.