PORTHOLE is a general term originally used to describe more or less any opening in the hull such as a gun-port.
DEADLIGHTS are the ‘windows’ which are fixed and non-opening.
PORTLIGHTS can be opened.
DECK-LIGHTS are prisms of rectangular or round shaped glass or acrylic set flush into the deck to give a constant stream of light below deck.
https://www.diy-wood-boat.com/Porthole.html#ixzz0nEnFj8k7
New Found Metals make a nice looking and (by reputation) well made product.
Beckson is another company that makes various ports.