A dub is a version of an anime with the original voice track replaced by performances in another language, most often English. Dubbing adapts a script for translated dialogue to match timing and lip movement, then records a new cast.
A dub is a translation performed twice: once on the page, where meaning must survive the crossing between languages, and once in the booth, where a line must fit mouths, timing, and an actor's breath while still sounding like something a person would say. Good dubbing is invisible craft; the arguments happen because everyone notices only the seams.
For a generation of Western fans the dub was not an alternative version of the series. It was the series: the names, voices, and jokes they grew up with, sometimes in editions edited for broadcast. Those versions are part of the medium's history and of their childhoods, and this site does not retcon either.
Modern dubs are produced closer to the source than ever, often in parallel with the original run. Where a dub and the original genuinely diverge, in a name, a line, or an edit, the difference is a fact about versions, and quizzes here declare which version they are testing rather than pretending only one exists. Dub casts have their own fandoms and convention circuits, and for many international viewers a dub performance is the canonical voice of a character in every way that matters to memory.
In use"Watching a series with its English voice performances is watching the dub."