concur v.

word-forming element meaning "together, with," sometimes merely intensive; it is the form of com- used in Latin before consonants except -b-, -p-, -l-, -m-, or -r-. In native English formations (such as costar), co- tends to be used where Latin would use con-.

Proto-Indo-European root meaning "to run."

It forms all or part of: car; career; cargo; caricature; cark; carpenter; carriage; carrier; carry; charabanc; charette; charge; chariot; concourse; concur; concurrent; corral; corridor; corsair; courant; courier; course; currency; current; curriculum; cursive; cursor; cursory; discharge; discourse; encharge; excursion; hussar; incur; intercourse; kraal; miscarry; occur; precursor; recourse; recur; succor.

It is the hypothetical source of/evidence for its existence is provided by: Greek -khouros "running;" Latin currere "to run, move quickly;" Lithuanian karšiu, karšti "go quickly;"Old Irish and Middle Welsh carr "cart, wagon," Breton karr "chariot," Welsh carrog "torrent;" Old Norse horskr "swift."