DIRECTRIX Meaning of DIRECTRIX in English [ dɪ'rɛktrɪks , dʌɪ- ]■ noun ( plural directrices -trɪsi:z ) Geometry a fixed line used in describing a curve or surface.OriginC18: from med. L., lit. 'directress'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004