CinCPAC
Admiral Husband E. Kimmel (Kimmel, Husband E.) was promoted to Commander in Chief Pacific (abbreviated to CinCPAC) in February 1941. The abbreviation was also used to mean his headquarters, and messages sent from there were said to have come from CinCPAC.
See also: Kimmel, Husband E.
You can find out more about CinCPAC in the following Osprey books:
CAMPAIGN 62 Pearl Harbor 1941; CAMPAIGN 30 Midway 1942; MEN-AT-ARMS 70 US Army 1941-45; MEN-AT-ARMS 342 US Army in WWII (1) The Pacific