english
1
general::
Need to urinate or defecate, as in He left to answer the call of nature. This euphemism may be dying out. [Mid-1800s]
American Heritage Idioms
2
general::
Phrase(s): the call of nature Euph. the need to go to the lavatory. • Stop the car here! I have to answer the call of nature. • There was no break in the agenda, not even for the call of nature.
McGrawhill's American Idioms And Phrasal Verbs