Currently in the UK we use the METRIC system for measuring weight but we used to use the IMPERIAL system.
Many countries still use the IMPERIAL system.
Below is a comparison table which may help understanding of the difference.
IMPERIAL WEIGHT METRIC EQUIVALENT
4oz (Quarter Pound) 113 grams
8oz (Half-Pound) 227 grams
16oz/1lb (One Pound) 454 grams
Although we are obliged to use Metric scales in our shop, all staff are trained to know the difference, so when a customer asks for 'a Quarter of' we can give them exactly what they want.