Fixed Deposits can be termed as deposit of money generally with banks, finance company or any large corporation for specific term on specific interest rate. It is a great way of earning more interest rates than keeping funds in your saving accounts. Interest can be earned on depending upon available options like Cumulative, Annually, Quarterly etc. Interests earned from fixed deposits are taxable & includes in your Interest income.
Bonds are debt security. When you purchase a bond, you are lending money to issuer and in return it provides you with a bond in which it promises to pay a specified rate of interest throughout the period of bond & repay the principal amount when it matures. Thus a bond is like a loan in which the issuer is borrower (debtor), the holder is the lender (creditor) & the coupon is interest rate.
Interests earned from bonds are taxable & includes in your Interest income, but bonds for more than 3years get the indexation benefits.