1. To make contact with another person. I'm going to link up with my friends after we're finished eating dinner, if that's all right. You should definitely link up with Nancy while you're in Tokyo.

2. To create or establish a connection to something else. I linked up with the company database to retrieve the documents that I need. The TV is just trying to link up with the Internet.

3. To create or establish a connection between one person or thing and someone or something else. In this usage, a noun or pronoun is used before or after "up." I can link my phone up with yours so that it sends you any photos that I take automatically. They linked me up with a machine that monitored my brain activity.