A brand of ugg boots owned by the US company, Deckers, which trademarked the generic term for the style of sheepskin boots that has been popular in Australia and New Zealand since the 1920s.
From the early 2000s, UGG Australia has become extremely popular in the US and Canada, but is derided in Australia. This is because the company is not Australian, and its boots are manufactured largely in China. Furthermore, Deckers has brought numerous copyright infringement lawsuits against Australian companies for using the word "ugg", all of which have been rejected since Australian IP law states that the term is generic in Australia and therefeore cannot be trademarked.
Canadian: "OMG, I love my UGG Australia ugg boots!"
Australian: "OMG, Fuck UGG Australia."