Oak-apple Day n (in Britain) May 29, the anniversary of the Restoration (1660), formerly commemorated by the wearing of oak apples or oak leaves, recalling the Boscobel oak in which Charles II hid after the battle of Worcester Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014