plutonium pit vs plutonium trigger

plutonium pit and plutonium trigger both are nouns.

Word	Noun	Adjective	Verb	Adverb
plutonium pit	Yes	No	No	No
plutonium trigger	Yes	No	No	No

As nouns, plutonium pit and plutonium trigger are synonyms defined as:

plutonium pit and plutonium trigger: a steel or beryllium sphere containing plutonium 239 that triggers nuclear fission when compressed by explosives

plutonium pit (noun)	plutonium trigger (noun)
a steel or beryllium sphere containing plutonium 239 that triggers nuclear fission when compressed by explosives	a steel or beryllium sphere containing plutonium 239 that triggers nuclear fission when compressed by explosives