lock down

verb6

1. •
   To secure (something).
2. •
   To blockade and lock (e.g. a building or campus) so as to prevent ingress or egress; to make the occupants (of an area) stay locked indoors for their safety.

   • Police have the area locked down until the situation is all-clear.
3. •
   To limit the use of (a computer network) to only users with permission.
4. •
   To make (an arrangement) secure, definite, or permanent; to fix.
5. •
   (slang) To cause (another person) to enter into an exclusive romantic relationship.

   • It took me some time, but I finally locked her down.
6. •
   To travel through a flight of locks on a waterway in a downhill direction.