Hack-and-Hold
"Hack-and-Hold" refers to facilities that, in order to be captured, must be hacked and the owning Empire prevented from re-hacking (resecuring) the facility for 15 minutes. Cavern facilities are also "hack-and-hold", but they need only be protected for 10 minutes.
This was the original way to capture a facility, but with the introduction of LLU facilities, this term was coined in order to distinguish between them. On the map screen, "hack-and-hold" facilities are distinguished by having an icon of a clock on either side of the facility's name.