spacecraft clock time vs SCLK

spacecraft clock time and SCLK both are nouns.

Word	Noun	Adjective	Verb	Adverb
spacecraft clock time	Yes	No	No	No
SCLK	Yes	No	No	No

As nouns, spacecraft clock time and SCLK are synonyms defined as:

spacecraft clock time and SCLK: the clock time given by a clock carried on board a spacecraft

spacecraft clock time (noun)	SCLK (noun)
the clock time given by a clock carried on board a spacecraft	the clock time given by a clock carried on board a spacecraft