A Bond in which an investor agrees to loan money to a company or government in exchange for a predetermined interest rate.

If a business wants to expand, one of its options is to borrow money from individual investors. The company issues bonds at various interest rates and sells them to the public. Investors purchase them with the understanding that the company will pay back their original principal plus any interest that is due by a set date

Bonds can be broadly classified into

Tax-Saving Bonds
Regular Income Bonds

Tax-Saving Bonds offer tax exemption up to a specified amount of investment.

Examples are:

ICICI Infrastructure Bonds under Section 88 of the Income Tax Act, 1961
NABARD/ NHAI/REC Bonds under Section 54EC of the Income Tax Act, 1961
RBI Tax Relief Bonds

Regular-Income Bonds, as the name suggests, are meant to provide a stable source of income at regular, pre-determined intervals. Examples are:

Double Your Money Bond
Step-Up Interest Bond
Retirement Bond
Encash Bond
Education Bonds
Money Multiplier Bonds/Deep Discount Bond
Similar instruments issued by companies are called debentures.