'lymphocyte-nonreactive' originates from Modern English, specifically the compounds 'lymphocyte' and 'nonreactive', where 'lymphocyte' derives from Neo-Latin 'lymphocytus' (from Greek roots) and 'nonreactive' is formed from the negative prefix 'non-' + 'reactive'.

'lymphocyte' changed from 19th-century Neo-Latin 'lymphocytus' (from Greek 'lympha' meaning 'clear fluid' + 'kytos' meaning 'cell') and eventually became the modern English word 'lymphocyte'. 'nonreactive' was formed in Modern English by prefixing 'non-' to the adjective 'reactive' (from Latin/French roots of 'react').

Initially the components referred separately to 'a clear-fluid cell' ('lymphocyte') and to the quality of 'reacting' or not ('non-' + 'reactive'); over time the compound has come to mean 'not producing or showing a lymphocyte response' in immunological contexts.