It is like another person going into business with you. EXAMPLE: You need help with your business, but on a higher level than staff - so you team up with someone and they can share a great deal of the management/work load. Hope I've helped
Partners are true staff members who usually work for a percentage of the profits. They are doing a large portion of the work. If they are just temporary, you should just pay them and cut them loose.
There are other definitions of partners too.... you get silent partners who simply provide funding without interfering with the running of the company at all. Companies can also partner with each other, a web development company may partner with a web marketing company so that they can present joint proposals for contracts thus potentially increasing their chances of winning the contract which they may not have been able to do as 2 separate bids