ὄρνυμι * ὌΡΩ is the Root from which most tenses are formed ὄρθαι contr. for ὀρέσθαι to the Med also belongs the pf. ὄρωρα (once ὤρορε)
radical sense to stir, stir up: esp.,
1.of bodily movement, to set on, urge on, incite, Il., Hes.: —c. inf., Ζεὺς ὦρσε μάχεσθαι urged him on to fight, Il.:—Mid., with perf. ὄρωρα, to move, stir oneself, εἰσόκε μοι φίλα γούνατ᾽ ὀρώρηι while my limbs have power to move, Hom.; aor1 imperat. ὄρσεο, ὄρσευ, ὄρσο rouse thee! up! arise! id=Hom.:—in hostile sense, to rush on, rush furiously, Il., Aesch., etc.