'lactation-promoting' is a compound of 'lactation' and the present participle 'promoting'. 'lactation' originates from Latin, specifically the word 'lactatio' (from 'lactare' / 'lac' meaning 'milk'). 'promote' originates from Latin, specifically the word 'promovere', where 'pro-' meant 'forward' and 'movere' meant 'to move'.

'lactation' entered English via Late Latin 'lactatio' from Latin; 'promote' developed from Latin 'promovere' to Old French 'promouvoir' and then into Middle English (e.g. 'promoten'/'promote'). The compound adjective 'lactation-promoting' is a modern English formation combining these elements.

Initially, 'lactation' referred simply to milk secretion and 'promote' meant 'to move forward' or 'advance'; over time, combined as 'lactation-promoting' it has come to mean 'encouraging or increasing milk production'.