trial vs pilot program

trial and pilot program both are nouns.

Word	Noun	Adjective	Verb	Adverb
trial	Yes	No	No	No
pilot program	Yes	No	No	No

As nouns, pilot program is a hyponym of trial; that is, pilot program is a word with a more specific, narrower meaning than trial:

trial (noun)	pilot program (noun)
the act of testing something	activity planned as a test or trial
(law) the determination of a person's innocence or guilt by due process of law	a program exemplifying a contemplated series; intended to attract sponsors
the act of undergoing testing
trying something to find out about it
an annoying or frustrating or catastrophic event
(sports) a preliminary competition to determine qualifications