English

Noun

ancestrix ‎(plural ancestrices or ancestrixes)^[1]

1. A female forebear or ancestor; a predecessoress.^[1]

References

1. 1 2 “Ancestor” defined identically by:
     Ancestors: Webster’s Quotations, Facts and Phrases (2008, ICON Group International, Inc.) on page 371, and by:
     Correctives: Webster’s Quotations, Facts and Phrases (2008, ICON Group International, Inc.) on page 205, as:
       Ancestor. An ancestor is a parent or (recursively) the parent of an ancestor. […T]he correct female form of the word is “ancestrix”, pl: “ancestrixes” or “ancestrices”.