'proteic' is formed in modern scientific English from 'protein' + the adjective suffix '-ic'; 'protein' itself was coined from Neo-Latin/Modern scientific usage based on the Greek word 'proteios' (from 'protos') meaning 'first' or 'primary'.

'protein' was introduced in the 19th century (coined from Greek-rooted Neo-Latin), and the adjective 'proteic' was later formed from 'protein' by adding the suffix '-ic' to denote 'of or relating to protein'.

Initially connected to the idea of 'primary' (from Greek 'protos'), the modern scientific sense settled on 'relating to proteins'; a rarer figurative sense has developed meaning 'protean' or 'changeable'.