ice formed below the surface of a body of water that attaches either to a submerged object or to the bottom.
Origin of anchor ice
An Americanism dating back to 1805–15
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for anchor ice
Canadian ice that forms at the bottom of a lake or river
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