Block

From the dictionary, i learned that a block is a section of a street between two roads that cross the street.
I wonder if two roads stop at the street, only one side of the street is "blocked" between the roads, what a block would be?
If roads stop at both sides of the street and do not align with each other, what a block would be?
The Cambridge Dictionary says "block" is mainly used in the US, what is the British equivelent?
Thank you very much for your help.