Union Jacks and Southern Skies - appendix one
Union Jack Or Union Flag?
Throughout this document, the British flag has been referred to as the "Union Jack". Officially, it is called the "Union Flag". Strictly speaking, "the Union Flag becomes a Union Jack only when flown from the jackstaff at the bow of a vessel of the Royal Navy". However, "the practice of calling it the Union Jack in almost all circumstances is so widespread as to make it the flag's unofficial name".(34)
Union Jacks and Southern Skies
Australian Nationalism Information Database - www.ausnatinfo.angelfire.com/~natinfo