'foam-reducing' originates from Modern English, a compound of the noun 'foam' and the present participle 'reducing' (from the verb 'reduce'), where 'foam' meant 'froth' and 'reduce' meant 'make smaller or lessen.'

'foam' changed from Old English (e.g. Old English forms such as 'fām' / 'fōm' and Middle English 'fome') into the Modern English 'foam'. 'Reduce' derives from Latin 'reducere' ('re-' + 'ducere'), passed into Old French and Middle English as 'reduce' before becoming the modern verb 'reduce'; the present participle formed as 'reducing'. The compound 'foam-reducing' is a modern English formation combining these elements.

Initially, 'foam' referred simply to froth and 'reduce' (from Latin 'reducere') literally meant 'lead back'; over time 'reduce' came to mean 'make smaller' or 'lessen'. The compound came to mean 'intended to lessen foam' in technical and everyday usage.