siege vs military blockade

siege and military blockade both are nouns.

Word	Noun	Adjective	Verb	Adverb
siege	Yes	No	No	No
military blockade	Yes	No	No	No

As nouns, siege and military blockade are synonyms defined as:

siege and military blockade: the action of an armed force that surrounds a fortified place and isolates it while continuing to attack

Other synonyms of siege include beleaguering, besieging.

siege (noun)	military blockade (noun)
the action of an armed force that surrounds a fortified place and isolates it while continuing to attack	the action of an armed force that surrounds a fortified place and isolates it while continuing to attack