'expectancy' originates from Latin, specifically the word 'exspectantia,' where 'ex-' meant 'out' and 'spectare' meant 'to look at.'

'exspectantia' transformed into the Old French word 'expectance,' and eventually became the modern English word 'expectancy' through Middle English.

Initially, it meant 'the act of looking out for something,' but over time it evolved into its current meaning of 'anticipation or hope for something.'