New York minute vs split second

New York minute and split second both are nouns.

Word	Noun	Adjective	Verb	Adverb
New York minute	Yes	No	No	No
split second	Yes	No	No	No

As nouns, New York minute and split second are synonyms defined as:

New York minute and split second: a very short time (as the time it takes the eye to blink or the heart to beat)

Other synonyms of New York minute include blink of an eye, flash, heartbeat, instant, jiffy, trice, twinkling, wink.

New York minute (noun)	split second (noun)
a very short time (as the time it takes the eye to blink or the heart to beat)	a very short time (as the time it takes the eye to blink or the heart to beat)