The word burglar, which predates burglary in English by about 250 years, was borrowed in the thirteenth century from the Anglo-Latin word burglator, and that's from the Medieval Latin word burgator. The l in the middle of the world was not natural and it was added because of influence from another Latin word for "thief", latro. Burgator was based on the Latin verb burgare, meaning "to break open", and that's from burgus, a noun meaning "castle" (apparently the word was formed on the notion of breaking open a castle's defenses). The verbs burgle and burglarize independently developed as humorous back-formations of burglary on different sides of the Atlantic in the 1860s.
Hello! I'm Adam Aleksic, a senior studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy trivia, politics, vexillology, geography, board games, conlanging, art history, and law.