Hilary of Poitiers (?h?l?r?) n (Biography) Saint. ?315??367 ad, French bishop, an opponent of Arianism. Feast day: Jan 13 or 14Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014