"square stone for building or paving," mid-14c., from Old French aisseler, Medieval Latin arsella "a little board or shingle," diminutive of Latin assis "a board, plank," also spelled axis, which is perhaps not the same axis that means "axle." De Vaan regards the Latin spelling axis as a hyper-correction. The stone sense is peculiar to English. The meaning "thin slab of stone used as facing on a wall" is from 1823.
updated on September 26, 2022