What is the greek root of verbatim?

The Greek root of "verbatim" is verbum, meaning "word". While not strictly a Greek *root* in the sense of a morpheme combined with other morphemes to build words, "verbatim" is derived from the Latin phrase "verbum pro verbo," meaning "word for word." "Verbum" itself ultimately derives from the Proto-Indo-European root *wer- (to speak).