'vaccinator' originates from Latin, specifically the verb 'vaccinare' (from 'vacca'), where the root 'vacca' meant 'cow'. The English agent suffix '-or' was added to form a noun meaning 'one who vaccinates.'

'vaccinator' developed from the late 18th-century verb 'vaccinate' (from Latin 'vaccinare', based on 'vacca' 'cow'), with the English agentive suffix '-or' attached to create 'vaccinator' in modern English.

Initially related specifically to inoculation with material derived from cows (cowpox) — 'to vaccinate' originally meant 'to inoculate with cowpox' — but over time it broadened to mean administering any vaccine; 'vaccinator' now means any person who administers vaccines.