A bond is a loan made to an issuer.  If a company or a government issues a bond, it sets a purchase price, and promises to pay a certain amount regularly to the bond holder until some time when the issuing price must be repaid.  In essence, the holder of the bond has loaned money to the issuer and gets periodic interest as payment.

For many bonds, the bond holder can sell the bond on the bond market, after which the interest payments will go to the new bond holder.  The price will not necessarily be the same as the issuing price, but will depend on a comparison with the interest rates that one can get from other sources at the time of the sale.  Also, as with stocks, the bond holder can reinvest the interest by buying other bonds, with the potential for additional growth of the overall investment.