πῆχυς the fore-arm, from the wrist to the elbow, Lat. ulna, Xen., etc.:— generally, the arm, ἀμφὶ υἱὸν ἐχεύατο πήχεε λευκώ Il., etc. the centrepiece, which joined the two horns of the bow, Hom. in pl., the horns or sides of the lyre, opp. to ζυγόν the bridge, Hdt. as a measure of length, the distance from the point of the elbow to the end of the little finger, Lat. cubitus or ulna, a cubit or ell, containing 24 δάκτυλοι or 18 1/4 inches, Hdt.: the π. βασιλήιος was longer by three δάκτυλοι, 27 δάκτυλοι or 20 1/2 inches, Hdt. a cubit-rule, as we say "a foot-rule, " Ar.