1911 Encyclopædia Britannica/Ashlar

​ASHLAR, also written Ashler, Ashelere, &c. (probably from Lat. axilla, diminutive of axis, an axle), hewn or squared stone, generally applied to that used for facing walls. In a contract of date 1398 we read—“Murus erit exterius de puro lapide vocato achilar, plane incisso, interius vero de lapide fracto vocato roghwall.” “Clene hewen ashler” often occurs in medieval documents; this no doubt means tooled or finely worked, in contradistinction to rough-axed faces.

An “ashlar piece” in building is an upright piece of timber framed between the common rafters and the wall plate.