A "treasure room" is a special place where valuable or prized items are kept safe and stored. It's like a room full of treasures, like gold, jewels, or important artifacts. Full definition
Treasure, traps, and monster placements will always be new and fresh, though sometimes you'll come across treasure rooms where you have no hope of claiming their spoils if you do not have a very specific character class with special abilities. (indiegamereviewer.com)
Upper left treasure room contents: Secret Book We recommend Anna for this room. (gamesradar.com)
Left treasure room contents: Boots and Seraph Robe If you want to head off the thieving Ruffian, move your squad along the left and middle paths. (gamesradar.com)