Cryptonym: KAPOK
National Archives, Research Aids: Cryptonyms and Terms in Declassified CIA Files: https://www.archives.gov/iwg/declassified-records/rg-263-cia-records/second-release-lexicon.pdf
KAPOK is identified as "a cable indicator for document sensitivity".
Memorandum re Reclassification of Document, 9/12/62: In terms of sensitivity, KAPOK seems to be the highest level of compartmentalization, then RYBAT, then EYES ONLY.
National Archives, Records of the Office of Strategic Services, (RRG 226): Entry 214
This document list supports the word KAPOK first emerges in files of the Officer of Strategic Services in a nineteen forty-six memo that seeks to acquaint Washington with the KAPOK system “with present or contemplated operations”. https://www.archives.gov/iwg/declassified-records/rg-226-oss/entry-214.html
National Archives, Records of the Office of Strategic Services, (Record Group 226) 1040-1947, Entry 210, Boxes I-538
This Office of Strategic Services memo regards KAPOK material as a type of restricted information akin to the later usage by the Central Intelligence Agency. This would infer the Agency likely converted at least in part some of the KAPOK system or at least one of its classification markers from the OSS. https://www.archives.gov/files/iwg/declassified-records/rg-226-oss/entry-210.pdf
CIA, Library Reading Room, Distribution of Cables Based On Sensitivity Indicators, KAPOK and RYBAT
A nineteen fifty-two document established the earlier policy for distributing Agency cables based on sensitivity indicators such as KAPOK. The document states “Basic sensitivity indicators are KAPOK and RYBAT. These indicators are for general use and serve to limit the distribution of cables as effected within Headquarters by the Message Center. Cables received without such indicators which by content or prior reference warrant treatment as KAPOK or RYBAT will be so handles by the Message Center.” https://www.cia.gov/library/readingroom/docs/CIA-RDP78-04718A000400070007-5.pdf
This document reveals the definition of CIA terms by Agency officer Russell Holmes, a man noted to be among the most familiar and able to decipher such material states that KAPOK is a sensitivity indicator and contains the note “Less than five” which may refer to the amount of people certain materials would be disseminated among.