'Tidemark' definitions:
Definition of 'tidemark'
From: WordNet
noun
Indicator consisting of a line at the highwater or low- water limits of the tides
Definition of 'Tidemark'
From: GCIDE
- Tidemark \Tide"mark\, n.
- 1. a mark on a shore line indicating the normal level of the water at high tide, caused by the action of the flowing water; sometimes also used for the mark left at the point of the normal low tide; -- called also high water mark. [PJC]
- 2. [fig.] the maximum level which some activity has reached and from which it has declined; -- called also {high water mark}. [PJC]