An open, flat area on a ship where passengers can sit or lie in the sun. On a boat, a 'deck' is one of the floors, and the sundeck is the top one that is open to the sky rather than enclosed. The word is also used away from ships — a wooden platform built out from a house, or a flat roof area at a hotel or swimming pool where people put out chairs to sunbathe, can be called a sundeck too. It has a comfortable, holiday feeling: cruise ships and hotel brochures use it constantly. You will see it written as one word 'sundeck' and as two words 'sun deck'; both are normal, and the two-word form is a bit more common in British writing.

（郵輪的）日光甲板；（旅館、住家的）曬太陽的露台、觀景平台