Meaning

noun a solid section between two crenels in a crenelated battlement

originBorrowed from French merlon, from Italian merlone (“merlon”), from merlo (“merlon”) + -one (suffix forming augmentatives). Merlo is derived from Late Latin merulus, merlus, possibly from Latin merula (“blackbird”) (as merlons resemble a row of birds perched on a wall), from Proto-Indo-European *h₂ems- (“black; blackbird”). The English word is cognate with Italian mergolo (“battlement; pinnacle”),…

Etymology from Wiktionary, CC BY-SA 3.0