one’s (w?nz) adjformal a third-person singular possessive corresponding to one. See onecontraction of1. one is2. one hasCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014