time vs period of time

time and period of time both are nouns.

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

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

time: an indefinite period (usually marked by specific attributes or activities)
period of time: an amount of time

Other hypernyms of time include period, time period.

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

time: a period of time considered as a resource under your control and sufficient to accomplish something
period of time: an amount of time

Other hypernyms of time include period, time period.

time (noun)	period of time (noun)
the continuum of experience in which events pass from the future through the present to the past	an amount of time
rhythm as given by division into parts of equal duration
an instance or single occasion for some event
a person's experience on a particular occasion
an indefinite period (usually marked by specific attributes or activities)
the period of time a prisoner is imprisoned
a reading of a point in time as given by a clock
the fourth coordinate that is required (along with three spatial dimensions) to specify a physical event
a period of time considered as a resource under your control and sufficient to accomplish something
a suitable moment

time (verb)	period of time (verb)
measure the time or duration of an event or action or the person who performs an action in a certain period of time
regulate or set the time of
adjust so that a force is applied and an action occurs at the desired time
assign a time for an activity or event
set the speed, duration, or execution of