include vt. [Usenet] 1. To duplicate a portion (or whole) of another's message (typically with attribution to the source) in a reply or followup, for clarifying the context of one's response. See the discussion of inclusion styles under "Hacker Writing Style". 2. [from {C}] `#include <disclaimer.h>' has appeared in {sig block}s to refer to a notional `standard {disclaimer} file'.