sidebone (?sa?d?b??n) n (Veterinary Science) (often plural) ossification of the lateral cartilages in a horse’s footCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014