A jobber is a full-line wholesaler capable of providing a variety of retailservices including product distribution, ordering, stocking, advertising, financial information and reporting. See rack jobber.

1. One that buys merchandise from manufacturers and sells it to retailer s.

2. One that works by the piece or at odd jobs.

3. Chiefly British, a middleman in the exchange of stocks and securities among brokers.

4. Manufacturer, tradesman, or wholesaler who deals in small lots of goods or 'jobs,' or acts as an agent, middleman (intermediary), or a sub-contractor, and usually does not deal directly with the principal customer.

Source: http://www.thefreedictionary.com/jobber