A short, informal way of writing 'till', which itself means 'until' — up to a certain time. You will see it in song titles, text messages, shop signs and handwritten notes: 'Open til late', 'Wait til you see this'. It is not wrong so much as casual: it is the spelling people reach for when they are writing fast or writing to be heard rather than read. In a school essay or a business email, write 'until'. Though actually, there is a small mess here that even native speakers argue about. 'Till' is the older word — it is a real English word hundreds of years old, not a chopped-off 'until'. So when people write 'til' with one L, and especially when they write ''til' with an apostrophe, they are 'correcting' a word that never needed correcting. All three (until, till, til) are used, all three are understood, and no one will misunderstand you. Note also that 'til' can start a longer stretch: 'from Monday til Friday', 'we danced til morning'.