Great Britain and Northern Ireland
I'm not sure what you mean by 'special name', but the official name for the British flag is: Union Jack
The term "Union Jack" is not considered correct because a Jack is a flag flown from a ship and British merchant ships fly the Red ensign and the Royal Navy flies the White Ensign. The Official title of the Flag of the United Kingdom is the "Union Flag" and unoffically "British Flag" although this term might be considered controversial in Northern Ireland
The U.k
Scotland
Union Flag, or more casually the Union Jack
The Union Jack is the nickname of the UK flag.
New Zealand is a commonwealth country which derived from English origins thus the Union Jack.
The same flag that it flies at other times - the Union Flag - sometimes incorrectly called the Union Jack.
The Union Jack became the official flag of Britain in 1801. It was created by combining the crosses of St George (England), St Andrew (Scotland), and St Patrick (Ireland) following the Act of Union, which united Great Britain and Ireland. The design symbolizes the unity of the nations within the United Kingdom.
The jack refers to the jackstay of a ship, on which the Union Jack would be displayed. Strictly speaking the flag should be called the Union Flag, but Union Jack is well known. Actually, the union jack is what the flag is called out at sea, but the union flag is what they call it on land.
Because Samoa is an independent country, not a British colony.
because before Australia became a republic (independent country) it was ruled by England. Australia still has strong ties with england, so the union jack is on the flag to show this relationship.