Sentence:  For example, when a team of five players enters the Sunken Temple <WSD>instance</WSD> in "World of Warcraft", they will battle many monsters, but they will not encounter other players even though several teams of players may be experiencing the Sunken Temple at the same time. 
Meaning of the word marked with <WSD> tags:  A dungeon or other area that is duplicated for each player, or each party of players, that enters it, so that each player or party has a private copy of the area, isolated from other players.