XAUUSD is the market symbol for gold priced in US dollars, where XAU represents one troy ounce of gold and USD is the US dollar. The quote shows how many US dollars buy one troy ounce of gold, so at XAUUSD = 2,350, one troy ounce is worth USD 2,350.
You trade XAUUSD as a Gold CFD, a position on the price movement without owning the physical metal, which is what sets it apart from holding gold bullion. Go long if you expect the price to rise and short if you expect it to fall. The pair is quoted as the US dollar value of a single troy ounce.
XAUUSD moves on interest rates, inflation expectations, US dollar strength, bond yields, central bank policy, geopolitical risk, and safe-haven demand. A stronger US dollar usually weighs on the price, while rate cuts and risk-off conditions tend to lift it.
Say XAUUSD is trading at 2,350 and you expect gold to rise. You open a long Gold CFD position on five troy ounces using 20:1 leverage, so the full position is worth USD 11,750 while your margin is only a fraction of that. Gold climbs to 2,400 and you close.
Your profit is: (2,400 - 2,350) √ó 5 = USD 250
Had gold instead fallen to 2,300, the same move against you would cost USD 250. These prices are illustrative.