a hand level for determining elevations and angles of slope.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a surveying instrument consisting of a spirit level and a sighting tube, used to measure the angle of inclination of a line from the observer to another point
Word Origin for Abney level
C20: named after Sir William Abney (1843–1920), British chemist and physicist
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012