threshold vs starting time

threshold and starting time both are nouns.

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

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

Other hypernyms of threshold include beginning, commencement, first, get-go, kickoff, offset, outset, showtime, start.

threshold (noun)	starting time (noun)
the sill of a door; a horizontal piece of wood or stone that forms the bottom of a doorway and offers support when passing through a doorway	the time at which something is supposed to begin
the entrance (the space in a wall) through which you enter or leave a room or building; the space that a door can close
the smallest detectable sensation
a region marking a boundary
the starting point for a new state or experience