Halfpenny (British pre-decimal coin)
The British pre-decimal halfpenny (pronounced HAY-pən-ee), once abbreviated ob. (from the Latin 'obulus'), is a discontinued denomination of sterling coinage worth 1/480 of one pound, 1/24 of one shilling, or 1/2 of one penny.
Source: Wikipedia — Halfpenny (British pre-decimal coin) (CC BY-SA 4.0)