Dictionary.com
definitions

true north

noun Navigation, Surveying.

the direction of the north pole from a given point.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for true north

true north

noun

the direction from any point along a meridian towards the North PoleAlso called: geographic north Compare magnetic north
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
true north in Science

true north

See geographic north.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.