The Collaborative International Dictionary
Merlon \Mer"lon\, n. [F., perh. fr. L. moerus, for murus a wall, through (assumed) dim. moerulus.] (Fort.) One of the solid parts of a battlemented parapet; a battlement. See Illust. of Battlement.
Douglas Harper's Etymology Dictionary
"solid part of a battlement," 1704, from French merlon (17c.), from Italian merlone, augmentative of merlo "battlement," perhaps a contraction of mergola, diminutive of Latin mergae "two-pronged pitchfork."
Wiktionary
n. (context architecture military English) Any of the projections between the embrasures of a battlement
WordNet
n. a solid section between two crenels in a crenelated battlement
Wikipedia
A merlon is the solid upright section of a battlement or crenellated parapet in medieval architecture or fortifications. Merlons are sometimes pierced by narrow, vertical embrasures or slits designed for observation and fire. The space between two merlons is called a crenel, and a succession of merlons and crenels is a crenellation. Crenels designed in later eras, for use by cannons, were also called embrasures.
Usage examples of "merlon".
To an observer on the more commodious east bank, it appears to be a rectangular bartizan jutting from the rock, a bartizan four stories high at the side he sees, whose flat, merloned roof terminates against the cliff.
The askew merlons all showed cracks and chipsrecent, unweathered ones.
To one of the merlons, a jutting stone stub between two embrasures, a stripped pine trunk was lashed tight.
James climbed up on the wall, his youth as a thief giving him the keen balance and steel nerves needed to step atop the merlons of the wall and stare into the distance.
Of course, she had to concentrate fairly hard to keep the doorways from collapsing or the merlons from drying out and falling over the side of the towers, but out of the corner of her eye she could see the sea serpent undulating gently to her tune and even Cordelia seemed impressed.
All that remained above ground of the outlying structures were the toothy merlons and the tops of some of the towers.
He wedged himself between a pair of merlons and looked down at the sprawling disorder of the brochs and walls, wards and ruins, sheds, huts, and pigsties.
Wall as it was known of old rose to a height of four-score spans from the rocky, uneven ground to the jagged merlons which formed its battlements.
She leaned against one of the merlons of the embattled parapet, her eyes on the spot where he should emerge from the stairs, and thus she waited, her eyes haggard, her face drawn.
The wall had merlons and embrasures, but not a single patch of musket smoke showed in those de fences which meant that the castellation was false and there was no fire step on the wall's far side where defenders could stand.
The purple shadow of the curtain wall lay unbroken across the courtyard, but the sky was pale blue without a cloud, and on the western merlons the sunlight lay sharp and bright.
Soot stains marked some of the arrow loops, and here and there a crack or a missing merlon could be seen in the curtain wall, but it seemed little enough from this distance.
From heer I can look down on2 thi terisses & litil villiges on thi roofs ov thi parapet merlons wif thi litle feelds on thi crenels & if I look rite down I can c thi flat green valey that is thi alure but I xpect nun ov this terminoloji meens much if u doan no mutch about cassils.