O for a means to disseminate information! (8,6)
I believe the answer is:
circular letter
'means to disseminate information' is the definition.
(type of letter)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for circular letter that I've seen before include "communication to more than one person!" , "Several people will be sent this" , "One may be copied to several people" , "description of second-in-command" .)