From Longman Dictionary of Contemporary Englishtide-markˈtide-mark noun [countable] 1 HEOa mark left on the beach by the sea, that shows how high the sea reached2 British English informalDHC a dirty mark left around the inside of a bath by the water
Examples from the Corpus
tide-mark• At the highest point of the rising damp there will be an ugly tide-mark. 