'peptide' originates from Greek, specifically the word 'peptidos' (from 'peptein'), where 'pept-' meant 'to digest'. 'rich' originates from Old English, specifically the word 'rice' (or 'ric'), where 'ric' meant 'powerful, wealthy'.

'peptide' changed from the German scientific term 'Peptid' and eventually became the modern English word 'peptide'. 'rich' changed from the Old English word 'rice' (also seen as 'ric') through Middle English and eventually became the modern English word 'rich'.

Initially, 'peptide' referred to substances related to digestion, but over time it evolved to mean 'a short chain of amino acids'. 'Rich' initially meant 'powerful' or 'wealthy' and evolved to include the sense 'abundant in', as in 'peptide-rich'.