'sound-absorbent' originates from Modern English, specifically the words 'sound' and 'absorbent', where 'sound' meant 'noise' and 'absorbent' meant 'able to absorb'.

'absorbent' comes from Latin 'absorbere' (via Old French/Medieval Latin forms and then Middle English), where Latin 'absorbere' combined elements meaning 'to suck in'; 'sound' as a noun ('noise') is attested in Old and Middle English and was combined in Modern English to form the descriptive compound 'sound-absorbent'.

Initially, 'absorbent' described materials that soak up liquids or substances; the sense was extended to energy forms (including sound), so the compound now specifically denotes the ability to take in or dampen sound.