English

electrolucent

From electro- + lucent.

Ancient Greek ἤλεκτρον ‘amber’

French electrum

French électro-

Proto-Indo-European *lewk- ‘bright’

Proto-Indo-European *lowkéyeti ‘to light up’

Proto-Italic *loukeō ‘to cause to emit light, to cause to shine, to…’

Latin luceō ‘to shine’

Latin lūcentem

Today it means

adj That emits light under the influence of electrons (typically, in an electron microscope)

Language periods are conventional ranges, not dates for this word.

Etymograph / electrolucent