The main difference between stock and bond is, stock is a financial instrument issued by a company offering some ownership for exchanging money. Generally stockholders are consider as the owner of the company. When the company gains profits, the stockholders get dividend but when the company unable to gain profits the stockholders get nothing. So there is no guarantee of return and the risk of investment is high.
On the other hand, bond is a debt instrument issued by the government or any company to raise capital and promise to pay back the money after the fixed time with interest. Its a long-term debt. Generally bondholders are lender of the company. So there is guarantee of return and the risk of investment is low.