when is the union jack called the union jack
Union Jack The terms Union Jack and Union Flag are both historically correct for describing the de facto national flag of the United Kingdom. Whether the term Union Jack applies only when used as a jack flag on a ship is a modern matter of debate.[9]
Union Jack When statically displayed, the hoist is on the observer's left. To fly the flag correctly, the white of St Andrew is above the red of St Patrick in the upper hoist canton (the quarter at the top nearest to the flag-pole). This is expressed by the phrases wide white top and broad side up.