[dewclin]

Also (possibly only amongst bankers in London):

- "Yard" - £billion (derived from the french "milliard")

[Symbiote]

Milliard was the standard British word for 1,000,000,000 until some point in the 1970s.

[simonh]

Then there was the British billion, which was a million million. The US version has taken over completely.

[gerikson]

https://en.wikipedia.org/wiki/Long_and_short_scales

[mejutoco]

Same in German.

[throw0101c]

From Numberphile, "How big is a billion?" (2012):

* https://www.youtube.com/watch?v=C-52AI_ojyQ

[twic]

Also "buck" and "bar", which I think are one and two million. Not uniquely British, but certainly used here.