What Does This Line Mean In Brokerage Account?

[RetiredAt49]

I understand that the below line means I received a dividend but why does it say margin at the end?

DIVIDEND RECEIVED DEVON ENERGY CORP NEW (DVN) (Margin)

 

[Done]

You have a margin account which allows you to buy a certain amount of securities on credit against collateral in your account. Holdings are classified as either cash or margin. Margin in this case means these can be used as collateral.

Fidelity has margin FAQs.