Eight of the lamps (or candles) on the Hannukah menorah symbolise the eight days of the holiday. One lamp is lit on the first day, two on the second, and so on. The centre branch holds the shamash ('helper' or 'servant'), which is used to light the other eight.
The menorah is mentioned in the Bible. In antiquity, according to Wikipedia, it was a symbol of both Judaism and Christianity; but in modern times it's primarily considered a symbol of Judaism. It's depicted on the coat of arms of the modern state of Israel (flanked on either side by an olive branch, with the motto 'Israel' in Hebrew script centrally at the bottom).
© Haydn Thompson 2021