'starch-reduced' is a modern English compound formed from 'starch' + the past participle 'reduced' (from 'reduce').

'starch' comes from Old English 'stearc' (from Proto-Germanic *starkaz) meaning 'stiff' (later the substance that makes things stiff); 'reduce' comes from Latin 'reducere' via Old French (e.g. 'reduire') and Middle English 'reduce'. The compound 'starch-reduced' is a recent coinage used in food labeling and product descriptions.

Individually, 'starch' originally referred to 'stiffness' and then to the substance causing stiffness; 'reduce' originally meant 'to lead back' (Latin). Combined in modern usage the compound means 'having the starch content reduced' (a food-processing or nutritional description).