'consistently' originates from Latin, specifically the word 'consistere,' where 'con-' meant 'together' and 'sistere' meant 'to stand.' 'Observed' originates from Latin, specifically the word 'observare,' where 'ob-' meant 'toward' and 'servare' meant 'to watch.'

'Consistere' transformed into the Old French word 'consister,' and eventually became the modern English word 'consist.' 'Observare' transformed into the Old French word 'observer,' and eventually became the modern English word 'observe.'

Initially, 'consistently' meant 'standing together,' but over time it evolved into its current meaning of 'regularly.' 'Observed' initially meant 'to watch over,' and this meaning has largely remained the same in modern usage.