A "contact" is someone in an organization whom you are able to speak with. Your contact can answer questions about the organization, or pass information on to other people in that organization.
For example, if your company uses software that's made by another company, you might have a "contact" at the company that made the software. The contact might be one of their salespeople, or one of the engineers who built the software.
We talk about "having" a contact:
Do you have any contacts at any local newspapers or blogs that you can ask about publicizing the event?
Contacts "belong" to someone:
I'll ask my contact in the sales department.