fox: [OE] Fox probably means literally ‘tailed animal’ – the fox’s brush being perhaps its most distinctive feature. It has been traced back to a prehistoric Indo-European *puk-, which also produced Sanskrit púcchas ‘tail’. In West Germanic this gave *fukhs, from which come German fuchs, Dutch vos, and English fox. The fox is also named after its tail in Spanish (raposa ‘fox’ is a derivative of rabo ‘tail’) and in Welsh (llwynog ‘fox’ comes from llwyn ‘bush’ – that is, ‘bushy tail’). [fox etymology, fox origin, 英语词源]