ancient lights
n (Law) (usually functioning as singular) the legal right to receive, by a particular window or windows, adequate and unobstructed daylight
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014