parcel bomb vs package bomb

parcel bomb and package bomb both are nouns.

Word	Noun	Adjective	Verb	Adverb
parcel bomb	Yes	No	No	No
package bomb	Yes	No	No	No

As nouns, parcel bomb and package bomb are synonyms defined as:

parcel bomb and package bomb: a thin explosive device inside an envelope or package and detonated when opened

Other synonyms of parcel bomb include letter bomb.

parcel bomb (noun)	package bomb (noun)
a thin explosive device inside an envelope or package and detonated when opened	a thin explosive device inside an envelope or package and detonated when opened