'electron-emitting' originates from Modern English, specifically the word 'electron' + 'emitting', where 'electron' ultimately comes from Greek 'ēlektron' meaning 'amber' and 'emit' derives from Latin 'emittere' meaning 'to send out'.

'electron' was coined in Modern/Scientific English in the 19th century from New Latin 'electron' (from Greek 'ēlektron'); 'emit' comes from Latin 'emittere' (em- 'out' + mittere 'to send') and passed into Middle English via Old French forms, eventually producing English 'emit' and its present participle 'emitting'; these combined give 'electron-emitting'.

Initially, 'ēlektron' referred to 'amber' (used in ancient observations of static electricity) and later named the subatomic particle 'electron'; 'emit' originally meant 'to send forth' and evolved to mean 'to give off' — together the compound now specifically means 'to give off electrons'.