The Proto-Celtic word *nawan
Word *nawan
Meaning nine, 9

Other words that might be of interest
*φelu ‘many’, *oino ‘one’, *dwei ‘two’, *dwā(w) ‘two’, *swexs ‘6, six’, *tri ‘three, 3’, *kʷetru ‘four’, *kʷenkʷe ‘five, 5’, *oljo ‘all’, *sextam ‘seven’