Is the O E in Orderves a Ligature?

The word fetis derives from the latin fetus, which never had an o in it. The preservation of this mistaken o e spelling in british english spellings of foetus is reflective of the languages generally more conservative orthography. In french words such as car meaning heart, ser meaning sister, and ef meaning eg, are all always written with o e as a ligature. There is one alphabet where the o e ligaature does have the status as a letter: international phonetic alphabet.