A role is a part someone plays or a function they perform: "she took on a management role". A roll is a turning movement, a small round loaf, or a list of names: "the ball rolled under the car", "a bacon roll", "the class roll". If you could substitute the word part, you need role.
The core difference
Role is a single-purpose noun. It means a part in a play or film, or by extension the function a person or thing performs in a system: a supporting role, the role of vitamin D in bone health, parental roles. It is never a verb.
Roll does far more work. As a verb it means to turn over and over, or to move on wheels: the coin rolled off the table. As a noun it can be something rolled up (a roll of tape), a small bread loaf (a cheese roll), a list of names (the electoral roll), or a continuous sound (a drum roll).
The test you can run
Substitute the word part. She played a part in the negotiations — that works, so the word is role. He played a part call — nonsense, so it is roll call.
If part fails, ask whether the word involves turning, wheels, a list, or food. Any of those points to roll. One useful hook: the e in role also sits in performer and theatre, where parts are played; roll shares its double l with ball, which is the thing that does it.
Where it goes wrong
The mistakes cluster in a handful of set phrases, so it is worth learning these outright:
- Role model — a person whose part in life others imitate. Never roll model.
- Roll call — reading out a list of names. Never role call, even though it feels like it involves people's roles.
- Payroll — originally a list of people to be paid, so it takes roll.
- On a roll — enjoying a run of success, from the momentum sense.
- Play a role in — contribute to. This is the one most often mistyped as roll.
The edge case
Watch for the double meaning in workplace writing. Roles and responsibilities is about job functions; rolling out a new system is about launching it in stages. Both appear in the same documents, which is exactly why spellcheck will not save you — both spellings are real words, so the error passes silently.
Also note that role has no verb form. If your sentence needs an action — rolling, rolled, rolls — the answer is always roll.
