A bond is basically a securitized loan, meaning it’s created and something sold to investors. This means it can be bought and sold from investor to investor.
Bonds are also sold to many parties, vs. a loan that’s typically a single lender. Instead of applying to a bank for a single $10m loan, a bond issuance could get sold off to 10,000 investors in $1000 increments.
And in terms of repayments, bonds pay interest according to the terms (eg. 5% for 10 years) and then return the principal at the end o the term vs. a loan that’s a combination of interest and principal during payments.