a raised, open area, as a roof, terrace, or ship's deck, that is exposed to the sun.
Origin of sun deck
First recorded in 1905–10
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
an upper open deck on a passenger ship
US, Australian and NZ a balcony or deck attached to a house, originally used for sunbathing
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012