'antibody-reactive' originates from Modern English, specifically the combination of 'antibody' and 'reactive', where 'antibody' is built from the prefix 'anti-' meaning 'against' and 'body' meaning 'organism body part', and 'reactive' comes from 'react' + the adjectival suffix '-ive' meaning 'tending to'.

'antibody' was coined in the late 19th century from 'anti-' + 'body' to name substances opposing foreign bodies; 'reactive' derives from Latin roots via verb 'react' (re- + agere) and the suffix '-ive'. The compound 'antibody-reactive' formed in modern biomedical English by combining these elements to describe a property that reacts with antibodies.

Initially, 'antibody' named substances that neutralize or bind antigens and 'reactive' described the tendency to respond; together the compound came to mean 'capable of being bound or detected by antibodies' in current biomedical usage.