Y-level n (Surveying) surveying a level mounted on a Y-shaped support that can be rotated Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
Y level
Y´ lev`eln.1.(Surv.) See under Y, n.Webster’s Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.