'pie' originates from Middle English, specifically the word 'pie' (also spelled 'pye'), where it referred to a small pastry or a mixed collection associated with the magpie's varied diet.

'pie' changed from Old French 'pye' (borrowed into Middle English) which in turn is linked to Medieval Latin 'pica' meaning 'magpie', and it eventually became the modern English word 'pie'.

Initially it was associated with a 'magpie' or a mixed collection (by analogy to the bird's habit of collecting varied items), but over time it evolved into its current primary meaning of 'a baked dish with a crust and filling'.