ˈtīd ə l adjective
Etymology: tide (I) + -al
1. : of or relating to tides : caused by tides : having tides : periodically rising and falling or flowing and ebbing
tidal waters
2. : moved or actuated by tides
a tidal motor
3. : dependent (as in regard to the time of arrival or departure) upon the state of the tide
a tidal steamer
a tidal train run in connection with a tidal steamer
also : navigable only at high tide
a tidal harbor
4. : of, relating to, or constituting tidal air
the tidal volume exhaled
• tid·al·ly -d ə lē, -li adverb