φᾰκ-ωτός · phak-ōtos — LSJ
lentil-shaped, provided with a lenticular terminal guard, provided with a lenticular screw-thread
lentil-shaped, of hot-water bottles, Archig. ap. Aët. 9.28, Orib. Fr. 116; provided with a lenticular terminal guard, [ἐκκοπεύς] Gal. 10.449; provided with a lenticular screw-thread, κοχλίας Hero Mech. 2.5 (ii p.286 Schmidt).