American vs. British idiom meaning
To those who speak British English: is it true that the idiom "to knock someone up" only means "to get somebody pregnant" when used in American English?
In support of that, neither Merriam-Webster nor Oxford dictionary mention that meaning, at least not their online versions. The Oxford dictionary, in fact, mentions a completely different meaning, something to do with the sports.
Can someone answer that?
I was also kind of curious as to what other idioms exist in one but not the other.