e/Head of tide

Information
has gloss	eng: Head of tide is the farthest point upstream where a river is affected by tidal fluctuations. This applies to rivers which flow into tidal bodies such as oceans, bays and sloughs. Though this point may vary due to storms and seasonal or annual differences in water flows, there is generally an average point which is accepted as the head of tide. A rivers tidal data is recorded at various locations downstream of this point. A rivers head of tide may be considered the upper boundary of its estuary.
lexicalization	eng: head of tide
instance of	(noun) the periodic rise and fall of the sea level under the gravitational pull of the moon tide