'spore-forming' originates from the combination of 'spore' and 'forming', where 'spore' refers to a reproductive cell capable of developing into a new individual without fusion with another cell, and 'forming' means creating or developing.

'Spore' comes from the Greek word 'spora', meaning 'seed' or 'sowing', and 'forming' is derived from the Old English 'formian', meaning 'to shape or create'.

Initially, it meant 'creating spores', and this meaning has largely remained the same in modern usage.