Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun porthole

2 senses of porthole

Sense 1
porthole -- (a window in a ship or airplane)
       => window -- (a framework of wood or metal that contains a glass windowpane and is built into a wall or roof to admit light or air)

Sense 2
port, embrasure, porthole -- (an opening (in a wall or ship or armored vehicle) for firing through)
       => opening -- (a vacant or unobstructed space that is man-made; "they left a small opening for the cat at the bottom of the door")