Pāvacana is another of those terms which is used fairly rarely, and which is not so far adequately treated in the dictionaries, which have treated it simply as “word”.
However, it is used rather consistently in the sense of the overall message of a teacher, especially a Buddha. We find it in this sense at SN 19.12, SN 19.17, SN 19.21, Pj 4, Thig 16.1, Thag 10.7, DN 16, and DN 32. It appears to be taken over from Brahmanical usage, since we find the phrase tevijjake pāvacane in the sense of someone knowing “the entire message of the three Vedas” at DN 3 and MN 95.
Clearly, “word” (as Ven Ānandajoti at DN 16), or “discourse” (as Ven Bodhi has at MN 95) is inadequate. Ven Bodhi in more recent translations uses “dispensation”, followed by Brahmali in his Vinaya translation. While we might use “message” in its pregnant spiritual sense, “dispensation” is probably the pragmatic choice.