A bond is an investment that represents a loan. They’re typically issued by governments and corporations who want to borrow money. A borrower who issues the bond promises to pay its lender, the bondholder.
The price of a bond and its interest rate are inversely correlated. That’s because a higher interest rate makes bonds more attractive to lenders and less attractive to borrowers. Higher demand and lower supply means higher prices. Lower yields make bonds less attractive to lenders and more attractive to borrowers. Lower demand and higher supply means lower prices.