a suffix occurring in loanwords from Latin, where it formed feminine nouns or adjectives corresponding to agent nouns ending in -tor ( Bellatrix ). On this model, -trix is used in English to form feminine nouns ( aviatrix; executrix ) and geometrical terms denoting straight lines ( directrix ).
Also, -trice .
[ -trix, s. -tric- ]
Usage . A suffix borrowed directly from Latin, -TRIX has been used since the 15th century on feminine agent nouns that correspond to a masculine (in Latin) or generic (in English) agent noun ending in -tor: aviator, aviatrix; legislator, legislatrix; orator, oratrix. Most nouns in -TRIX have dropped from general use, so that terms like aviatrix, benefactrix, legislatrix, oratrix, and proprietrix occur rarely or not at all in present-day English.
The forms in -tor are applied to both men and women: Her sister is the proprietor of a new restaurant. When relevant, sex is specified with the generic term: Amelia Earhart was a pioneer woman aviator. Legal documents still use administratrix, executrix, inheritrix, and the like, but these forms too are giving way to the -tor forms. See also -enne, -ess, -ette .