The Marriage License is the permission given by public authority to persons
who intend to (1) intermarry.

The Marriage Bond is a money guarantee that has its roots in colonial regulations.
Back then, because of the scarcity of ministers, the colony would require all persons wishing to be married by license to go to the county clerk. A bond was given with security that there was no lawful cause to prevent the marriage. Often the bondsman was someone other than the parent. The rich uncle was always a good candidate for bondsman. Once the bonds were completed, the license would be issued.

Of course, some got married by publishing (2) "banns." No bond or license was needed.

In Tennessee, three documents were created at the time of a marriage.

• The first was the marriage bond.
• The second was the license, wherein the court authorized the marriage, and the official signed the back to show that it had been performed.
• The ledger where the clerk copied some information from these two sources is known as the official marriage record, and is often the only surviving part of the record.

Charles A. Sherrill Tenn. State Library & Archives has furnished the following information on this subject according to his understanding of the material he has read.

• The groom had to assure the State that he was able to be legally married (was not already married to someone else, under age, or ineligible because of close blood relationship, etc.)
• This assurance was given in the form of a bond for a certain amount of money.  The friend or relative signed as the groom's security on the bond, commonly known as becoming a bondsman.
• If indeed the groom had been sued for violating the marriage contract, the bondsman would have had to pay any legal damages if the groom defaulted.
• No money actually changed hands at the time the bond was issued.
• This bonding procedure was used across Tennessee and in other southern states in the 19th century.

This document is created in response to a question about the $1250 marriage bond in Tennessee. 

Definitions by New World Dictionary

intermarry n.1. marriage between persons of different clans, tribes, races, religions, castes, etc.
                    2. marriage between closely related persons
banns n. pl. the proclamation, generally made in church on three successive Sundays, of an
                  intended marriage.