tidemark n : indicator consisting of a line at
the high-water or low-water limits of the tides
English
Pronunciation
Noun
tidemark
- a line (of seaweed or differently coloured sand etc) on the shore showing the level of high or low tide
- In the context of "by extension": any mark showing the limit of some past activity
- a line of scum left on
a bath tub when the water is drained away