Wordnet 3.0
NOUN (1)
1. 
 an extraordinary writ commanding an official to perform a ministerial act that the law recognizes as an absolute duty and not a matter for the official's discretion; 
 used only when all other judicial remedies fail; 
[syn: mandamus, writ of mandamus]
WordNet (r) 3.0 (2006):
writ of mandamus
    n 1: an extraordinary writ commanding an official to perform a
         ministerial act that the law recognizes as an absolute duty
         and not a matter for the official's discretion; used only
         when all other judicial remedies fail [syn: mandamus,
         writ of mandamus]