Entry lacking, Adler reports, in mss AF (and placed after omicron 577 in ms S).
According to the lexica of Trapp and Koukoules (*buzantinw=n bi/os kai\ politismo/s V 1.161ff), an orthomilion is a metal vessel (so also tau 1089). The word has been used instead for a concave part of a loom in Greek dialect since the late fourteenth century: see Hatzidakis below. The term is derived from Latin miliarium (cf. mu 1065); it being "upright" o)rqo-, and the Modern proverbial expression "fat as a 'thromili", led Koukoules to speculate it was wider at the base than the top.