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

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

Same in German.

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

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

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