'attenuate' originates from Latin, specifically the word 'attenuare', where the prefix 'ad-' (in assimilated form 'at-') meant 'to/toward' and 'tenuare' (from 'tenuis') meant 'thin'.

'attenuate' changed from Vulgar/Medieval Latin 'attenuare' and Old French forms such as 'atenoier'/'atenuer', and entered Middle English (e.g. 'attenuen'), eventually becoming the modern English 'attenuate'.

Initially it meant 'to make thin' or 'to make less dense'; over time it has broadened to mean 'to weaken, reduce, or lessen' in force, intensity, or effect (including specialized senses in biology and physics).