'sell-by' originates from the combination of the words 'sell' and 'by', where 'sell' means 'to exchange for money' and 'by' indicates a deadline or time limit.

'Sell-by' evolved from the practice of marking products with a date to ensure quality control and consumer safety.

Initially, it meant 'the date by which a product should be sold', and this meaning has remained consistent in modern usage.