starting time vs showtime

starting time and showtime both are nouns.

Word	Noun	Adjective	Verb	Adverb
starting time	Yes	No	No	No
showtime	Yes	No	No	No

As nouns, starting time and showtime are synonyms defined as:

starting time and showtime: the time at which something is supposed to begin

Other synonyms of starting time include beginning, commencement, first, get-go, kickoff, offset, outset, start.

starting time (noun)	showtime (noun)
the time at which something is supposed to begin	the time at which something is supposed to begin