• (n.) A woman who administers; esp., one who administers the estate of an intestate, or to whom letters of administration have been granted; a female administrator.
Ad·min`is·tra'trix noun [ New Latin ] A woman who administers; esp., one who administers the estate of an intestate, or to whom letters of administration have been granted; a female administrator. 
An outdated term for a female administrator -- the person appointed by a court to handle probate on behalf of someone who died without a will. Now, whether male or female, this person is called the administrator or, in some states, personal representative.
A woman who is appointed by the courts to administer a deceased person's estate in England, Wales and Northern Ireland; usually where there is no will or they are not named in the will.
a woman who is an administrator.