Dictionary.com
Thesaurus.com

clearing mark

American  

noun

Navigation.

  1. either of a pair of landmarks or marks on a mariner's chart lying upon a line clearingline along which a vessel can sail to avoid navigational hazards.

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.