A patron supports someone or something. A patron of a business supports the business by being a loyal customer. A patron of the arts helps support starving artists — financially, not with food rations.
The word patron comes from the Latin pater or patr- meaning "father." Think of how a father is supposed to financially support his kids. A patron of the arts is someone who shows his appreciation or support for the arts by donating money to arts organizations. And a patron of the Red Lobster is a frequent customer who can be seen in the same corner booth every Sunday night, noshing on cheddar biscuits.