embrasure vs porthole

embrasure and porthole both are nouns.

Word	Noun	Adjective	Verb	Adverb
embrasure	Yes	No	No	No
porthole	Yes	No	No	No

As nouns, embrasure and porthole are synonyms defined as:

embrasure and porthole: an opening (in a wall or ship or armored vehicle) for firing through

Other synonyms of embrasure include port.

embrasure (noun)	porthole (noun)
an opening (in a wall or ship or armored vehicle) for firing through	a window in a ship or airplane
	an opening (in a wall or ship or armored vehicle) for firing through