'aussie' originates from English, specifically a clipped form of the word 'Australian' formed by shortening 'Australia' or 'Australian' to 'Aus' and adding the diminutive suffix '-ie'. The element 'Austral-' ultimately comes from Latin where it meant 'southern'.

'aussie' changed from clipped forms of 'Australia'/'Australian' such as 'Aus' or colloquial 'Oz' and emerged as the informal 'aussie' in English (early 20th century). 'Australia' itself comes from Latin 'Australis' meaning 'southern'.

Initially it meant simply a shortened or affectionate form of 'Australian' (a person or thing from Australia); over time it retained that meaning but also extended to informal uses (e.g., referring to the Australian dollar or cultural labels), while remaining primarily colloquial and familiar in tone.