tide vs period of time

tide and period of time both are nouns.

Word	Noun	Adjective	Verb	Adverb
tide	Yes	No	Yes	No
period of time	Yes	No	No	No

As nouns, period of time is a hypernym of tide; that is, period of time is a word with a broader meaning than tide:

Other hypernyms of tide include period, time period.

tide (noun)	period of time (noun)
the periodic rise and fall of the sea level under the gravitational pull of the moon	an amount of time
something that may increase or decrease (like the tides of the sea)
there are usually two high and two low tides each day