Latin, "in discharge of one's duties," literally "out of duty," from ex "out of" (see ex-) + officio, ablative of officium "duty" (see office).
the president sat on the committee ex officio
the head of the department serves as an ex officio member of the board
ex
ex-
ex cathedra
ex libris
ex nihilo
ex officio
ex parte
ex post facto
exacerbate
exacerbation
exact
