Two suited overcalls
In a recent green point event playing 5 card majors partner as north opened 1c , I said may only be a two card suit and he may have 5 diamonds
East overcalled 2 nt which was alerted and I asked west the meaning and he said that it showed ANY two of the other 3 suits . I asked if there was an anchor suit and he said no , it didn’t have to as openers 1c was not a natural bid .
I was not sure of this but as West was a very senior EBU director I let it go
We got to our game contract so were not damages
My question is
is the above explanation correct and where about in the Blue Book Can I find it