logjam vs stoppage

logjam and stoppage both are nouns.

Word	Noun	Adjective	Verb	Adverb
logjam	Yes	No	No	No
stoppage	Yes	No	No	No

As nouns, stoppage is a hypernym of logjam; that is, stoppage is a word with a broader meaning than logjam:

Other hypernyms of logjam include arrest, check, halt, hitch, stay, stop.

logjam (noun)	stoppage (noun)
an immovable mass of logs blocking a river	the act of stopping something
any stoppage attributable to unusual activity	an obstruction in a pipe or tube
	the state of inactivity following an interruption