استاذأُسْتَاذٌ a foreign word, pronounced to be such because س and ذ do not occur in any one Arabic word, (Msb,) not found in the poetry of the pagan times, (Ibn-Dihyeh in TA art. ستذ,) nor in the language of those times, (Shifá el-Ghaleel, ibid.,) [arabicized from the Persian أُسْتَادْ,] A master: (MF:) a skilful man, who is held in high estimation: (Msb:) a preceptor; a tutor; a teacher: a craftmaster: (Ibn-Dihyeh; and Golius on the authority of Meyd:) [and so in the present day; as also أُسْتَا and أُسْطَا:] also applied by the vulgar to a eunuch; because he generally tutors children: (Shifá el-Ghaleel, and Ibn-Dihyeh:) pl. أُسْتَاذُونَ (Har p. 377) [and أَسَاتِيذُ and أَسَاتِذَةٌ; and vulgarly, in the present day, أُسْتَوَاتٌ and أُسْطَوَاتٌ].