I took the freedom to clean up these two synonymously used tags. "open-close" was less often used and had no description. There were two questions which used "open-close" without any referral to the OCP. For those, I simply deleted the tag rather than replacing it, because (even after reading them twice) the tag seemed to be expendable.
I hope this helps interested readers to find questions about the OCP more easily. New askers now have only one unique tag to choose from instead of two for the same topic.
P.S. In case someone wants to know, the two mentioned questions were AGPL alternatives for commercial software and Protocol for closing a socket connection .
