Roll or Role?
Role
The noun role means an actor's portrayal of a character or a job or function (of a person or thing). Examples:
Teddy was totally convincing in the role of Shylock.
What's your role onboard this aircraft?
The thermostat's role is to keep the temperature below 200 degrees so the casing does not melt.
Roll
The word roll has several meanings: To move by rotating or gather by rolling.
Roll the hay bale down the hill.
Roll over a bit. You're hogging the bed.
Roll your sleeves up and roll me the best cigar ever.
To move on wheels.
The skateboarders rolled past the park attendant, and he did not say a word.
A list.
Please check the nominal roll to ensure we're all present.
To start.
Roll the cameras.
Roll the credits.
A small round piece of bread (i.e., a bread roll).
Would you like butter on your roll?