Australian and New Zealand slang for trousers or pants, especially casual ones.
From Daks, an Australian company that manufactured trousers starting in 1931, named after founder Len Davies. Like 'kleenex' or 'bandaid,' the brand name became genericized to mean any trousers.
This is a perfect example of how brand names can completely take over a language—Australians say 'daks' so universally that most forget it originated from a single company name, just like 'aspirin' started as a Bayer trademark.
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