'anaphylactic' originates from Greek, specifically the word 'anaphylaxis,' where 'ana-' meant 'against' and 'phylaxis' meant 'protection.'

'anaphylactic' was formed in English in the early 20th century from 'anaphylaxis' plus the suffix '-ic,' and eventually became the modern English word 'anaphylactic.'

Initially, it meant 'relating to anaphylaxis,' and this meaning has remained the same in modern usage.