'localness' originates from English, specifically from the adjective 'local' plus the suffix '-ness'; 'local' comes from Latin 'locus' (via Late Latin 'localis') meaning 'place', and the suffix '-ness' comes from Old English '-nes(s)' meaning 'state or quality'.

'local' entered English via Late Latin 'localis' (and Middle French influence) and developed in Middle English as 'local'; the abstract noun-forming suffix '-ness' developed from Old English '-nes(s)'; together they formed the Modern English compound 'localness'.

Initially related to 'pertaining to a place' (from 'local'), the combined form came to mean 'the state or quality of being local'; this basic sense has been retained though technical uses (e.g., 'data localness') have extended the concept.