1ex·tra 
/ˈɛkstrə/ adjective
/ˈɛkstrə/ adjective 1 always used before a noun : more than is usual or necessary : additional
▪ a sandwich with extra mayonnaise ▪ She got a part-time job to earn some extra money. ▪ He gave us an extra week to finish the job. ▪ There's no extra charge for breakfast. ▪ Room service is/costs an extra $5. = You have to pay an extra $5 for room service. 2 : costing more : requiring additional payment
▪ Breakfast is included in the price, but room service is extra. [=you have to pay more for room service]
▪ a sandwich with extra mayonnaise ▪ She got a part-time job to earn some extra money. ▪ He gave us an extra week to finish the job. ▪ There's no extra charge for breakfast. ▪ Room service is/costs an extra $5. = You have to pay an extra $5 for room service.
▪ Breakfast is included in the price, but room service is extra. [=you have to pay more for room service]
go the extra mile — see mile
