Nik ‧ kei in ‧ dex, the /ˌnɪkeɪ ˈɪndeks/ BrE AmE ( also the Nikkei, the ˌNikkei ˈAverage )
a number that shows how well or badly ↑ share s have performed on the Tokyo ↑ stock exchange on a particular day. The number is based on the share prices of about 200 important companies. ⇨ ↑ Dow Jones Average , ↑ FT 100 Share Index , ↑ Hang Seng Index