'pre-legislative' is a compound formed from the prefix 'pre-' and the adjective 'legislative'. The prefix 'pre-' originates from Latin 'prae', meaning 'before'. 'Legislative' ultimately derives from Latin elements related to 'lex'/'legis' meaning 'law'.

'Legislative' entered English via Late Latin (legislativus) and Middle French forms and became established in Modern English as 'legislative'. The compound 'pre-legislative' is a more recent English formation using the productive prefix 'pre-' attached to 'legislative' to denote 'before legislation'.

The components originally conveyed 'before' (pre-) and 'relating to law' (legislative); combined, the term has consistently meant 'occurring or done before law-making' and has retained that preparatory sense in contemporary usage.