Anzac as a word is the acronym for Australian and New Zealand Army Corps. The soldiers in these both forces became known as Anzacs in a short time so it is possible to say the name of Anzac was used to describe the combination of both army corps during World War I.
Anzacs supported Britain, France, Italy, Japan and Russian Empire against Ottoman Empire, Germany and Austria-Hungary. They were brought in from training in Egypt to participate in Gallipoli landings. Mostly volunteers formed the Australian Imperial Force. Anzacs were formed in Egypt in 1915 and Anzac was a World War 1 army corps of the Mediterranean Expeditionary Force. They operated during the Battle of Gallipoli.
Australian, Turkish and New Zealand authorities are planning a big ceremony for the 100th anniversary of Anzac Day. It will be celebrating in Gallipoli-Turkey during the day of 25th of April, 2015. It is very important because there will not be another 100th anniversary.
The commemoration of Anzac Day is now a major event on Turkey's tourism calendar. Anzac Day services on the Gallipoli Peninsula are conducted by Turkey, Australia, New Zealand, France and Britain.