Lewis Short
(adverb) : quam-dĭu, less freq. quandĭu (mostly as two words, sometimes separated:
* Quam voluit diu,Cic. Q. Fr. 1, 1, 7)
* Interrog., how long ago? how long? quamdiu id factum est? Plaut. Capt. 5, 3, 3: quandiu apud vos ero,Vulg. Marc. 9, 18.
* Rel.
* Of time, as long as, until, during (class.): quamdiu potuit, tacuit,Caes. B. G. 1, 17: disces, quamdiu voles,Cic. Off. 1, 1, 2; Col. 12, 52, 13.
* Until (very rare): jubebat, ut semper id comesset, quamdiu tamen melius invenisset,Lampr. Elag. 29, 7.— Comp.: quamdiutius,Not. Tir. p. 35.—Sup.: ‡ quamdiutissime,Not. Tir. p. 35.
* Of inference, inasmuch as, in that (late Lat.): quandiu fecistis uni ex his fratribus,Vulg. Matt. 25, 40.
Charlton T. Lewis, Charles Short, A Latin Dictionary