The headword (presumably extracted from the quotation given, though the latter is omitted from mss AF) is aorist participle, masculine nominative plural, of an otherwise unattested verb ou)rotome/w.
[1] Quotation unidentifiable. (Adler initially suggested that it might come from 'FGrH 100', i.e. Dexippus, but in her consolidated addenda and corrigenda this was changed to FGrH 151, an anonymous Alexander-history.)