Australian and New Zealand Army Corps
The corps formed in Egypt in December 1914 under the command of Major General W. R. Birdwood, who brought the headquarters staff with him from India. Initially, it consisted of the 1st Division and the New Zealand and Australian Division. The full name being too large for constant use, especially in telegrams, the abbreviated form was adopted.
The word "Anzac" came to refer to not just the
corps, but also the men themselves ("Anzacs"), the beach where they
landed (Anzac Cove, now officially named Anzak Koyu by the government of
Turkey), the day of the landing in 1915 (25 April, Anzac Day, now a public
holiday in Australia and New Zealand) and the whole beachhead that they held
until December 1915.