The story
- Spanish · derived fromjaque“a bully”
- English todayjacklight
* jack + light. Probably from jack (“a male servant of any rank”), later associated with a boy servant or any boy, and later still with a knave: a rogue, thief, or deceitful man. * Possibly also related to Spanish jaque (“a bully”).
Etymology from Wiktionary, CC BY-SA 4.0.