Wiktionary
alt. 1 (context Australia UK NZ English) A length of sawn wood of cross section 4 inches by 2 inches, most often employed as structural framing lumber / timber. 2 (context UK military English) A cotton cloth 4 inches wide with lines two inches apart, conveniently torn into two inch lengths for cleaning a rifle barrel using a pull through. 3 (context Cockney rhyming slang English) A Jew. n. 1 (context Australia UK NZ English) A length of sawn wood of cross section 4 inches by 2 inches, most often employed as structural framing lumber / timber. 2 (context UK military English) A cotton cloth 4 inches wide with lines two inches apart, conveniently torn into two inch lengths for cleaning a rifle barrel using a pull through. 3 (context Cockney rhyming slang English) A Jew.
Usage examples of "four by two".
But I did come across one very peculiar item, a small green metal box six inches by four by two, with a circular control that was both switch and tuner, and two glassed-in dials with neither figures nor marking on them.