Until is a preposition and a conjunction. Until is often shortened to till or 'til. Till and 'til are more informal and we don't usually use them in formal writing.

Is the word until a preposition?

Until can be used in the following ways: as a preposition (followed by a noun): She continued to get a salary until the end of March. as a conjunction (connecting two clauses): I stayed there until he arrived. Baker is expected to be here until the end of the week.

Where is the use of until?

Until can function as a conjunction or a preposition. Here's how we use it. Until means 'up to the event mentioned'. I'll stay here until you come back.