'epithelial-promoting' is a compound of 'epithelial' and 'promoting'. 'epithelial' originates from New Latin 'epithelial', from Greek 'epithele'/'epithelium' where the prefix 'epi-' meant 'upon' and the root related to 'thele' (originally 'nipple' or 'surface'); 'promoting' comes from Latin 'promovere' where the prefix 'pro-' meant 'forward' and 'movere' meant 'to move'.

'epithelial' entered English via New Latin/Modern Latin from Greek 'epithele'/'epithelium', becoming 'epithelial' as an adjective in scientific usage; 'promovere' passed into Old French and Late Latin forms (e.g. 'promouvoir') and into Middle English as 'promoten'/'promote', with the present participle 'promoting' forming modern compounds like 'epithelial-promoting'.

Initially, the components meant 'upon' + (surface/nipple) for 'epithelial' and 'to move forward' for 'promote'; combined in modern scientific use they mean 'supporting or encouraging the forward development (growth/repair) of epithelial tissue', a specialized, technical sense.