Bond Yields
The annualized return you'd earn holding a bond, which moves inversely to the bond's price.
A bond's yield is the annualized return an investor earns from holding it, accounting for its price, its coupon (periodic interest payment), and the time left until it matures.
Yields and bond prices move in opposite directions: when a bond's price falls, its yield rises (the same fixed future payments are now cheaper to buy), and vice versa. This is why rising-rate environments are painful for existing bondholders — the market price of their bonds falls even though nothing about the bond itself changed.