Definition of chamber:
(n) :
a room, especially one used primarily for sleeping;
bedroom, sleeping room; an enclosed space. For example, a test chamber is typically a closable case where devices under test are placed
"dianne loaded a cartridge into the chamber of the rifle, then prepared to take aim at the target."
(v) :
to
enclose in a
room; to place in a chamber, as a round of ammunition
"she had chambered herself in her room, and wouldn't come out."