(1)Is there any more words to express to one that " Call of Nature'' ?
(2)When we use this is that fit for both calls?(Urine and ..)
(3)I'd like to learn this use in both formal and informal ways.
(4)What are the other synonyms for toilet?
Thanks in advance
I think you can use the term for either function.
There are many synonyms for the room:
loo, WC, bog (slang), etc
and for the vist:
take a leak, powder your nose, etc