Ten pounds, or the ten-pound note itself, in casual British speech. "Can you lend me a tenner?" is exactly how a British friend asks for £10. You can hear it as the money — "it cost me a tenner" — or as the physical piece of paper — "he pulled a tenner out of his wallet." It is informal and spoken: friends, shops, pubs, market stalls. You would not write it in a business email. It belongs to a small family of money words British people use every day: a fiver is £5, a tenner £10, a score sometimes £20, a grand £1,000. Two things to know for the real world. It is British, and mostly means pounds — an American would say "ten bucks," and although "tenner" is understood in Australia and Ireland for their own ten-dollar or ten-euro notes, an American speaker is much less likely to use it. Also, the sums have shifted with time: older speakers grew up when a tenner bought a proper night out, and you can still hear that in how they say it.