pilot experiment vs experiment

pilot experiment and experiment both are nouns.

Word	Noun	Adjective	Verb	Adverb
pilot experiment	Yes	No	No	No
experiment	Yes	No	Yes	No

As nouns, experiment is a hypernym of pilot experiment; that is, experiment is a word with a broader meaning than pilot experiment:

pilot experiment: a preliminary experiment whose outcome can lead to a more extensive experiment
experiment: the testing of an idea

Other hypernyms of pilot experiment include experimentation.

pilot experiment (noun)	experiment (noun)
a preliminary experiment whose outcome can lead to a more extensive experiment	the act of conducting a controlled test or investigation
	a venture at something new or different
	the testing of an idea

pilot experiment (verb)	experiment (verb)
	to conduct a test or investigation
	try something new, as in order to gain experience