'energy-converting' originates from Modern English, specifically by combining the noun 'energy' and the present participle 'converting'. 'Energy' ultimately comes from Greek 'energeia', where the root 'ener-' meant 'activity' or 'operation', and 'converting' derives from Latin 'convertere' (see 'convert') where 'con-' meant 'together/with' and 'vertere' meant 'to turn'.

'energy' passed from Greek 'energeia' into Late Latin and Old French forms before entering Middle English as 'energie' and becoming the modern English 'energy'. 'Convert' comes from Latin 'convertere', via Old French 'convertir' into Middle English 'convert'; combining the noun and present participle to form compounds like 'energy-converting' is a Modern English development.

Initially, Greek 'energeia' meant 'activity, operation' and Latin 'convertere' meant 'to turn around/transform'; over time these roots produced modern words whose combined sense is now 'converting energy from one form to another', which is the current meaning of 'energy-converting'.