'anti-pneumococcal' originates from a modern English compound formed by the prefix 'anti-' (from Greek) and 'pneumococcal' (from 'pneumococcus'), where 'anti-' meant 'against' and 'pneumo-'/ 'pneumo(coccus)' related to 'lung'/'a berry (coccus)'.

'anti-' was borrowed from Greek 'antí' into English as a productive prefix meaning 'against'; 'pneumococcal' derives from 'pneumococcus' (from Greek 'pneumōn' meaning 'lung' + 'kokkos' meaning 'berry'), and the adjective 'pneumococcal' entered modern medical English; the compound 'anti-pneumococcal' was formed in 20th-century medical usage to describe agents acting against pneumococci.

The components originally meant 'against' (anti-) and 'relating to the lung/berry-shaped bacterium' (pneumococcus); together they have retained the literal medical meaning 'against pneumococcus' and are used specifically for vaccines, sera, or drugs targeting Streptococcus pneumoniae.