Both till and until mean “up to a certain point in time”:
- Don’t worry, we won’t start without you. We’ll wait until/till you arrive.
- They don’t open until/till nine.
The main difference between the two words is that till is only used in informal style. So, in formal contexts, make sure to use until.
Till may also be spelt as ‘til. This form is most common in American English.
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