bi ‧ ro /ˈbaɪərəʊ $ ˈbaɪroʊ/ BrE AmE noun ( plural biros ) [countable] trademark British English
[ Date: 1900-2000 ; Origin: László Biró (1899-1985), the pen's Hungarian inventor ]
a pen with a small ball at the end that puts ink onto paper SYN ball point
⇨ ↑ pen 1