Courier
a runner, messenger
Precursor
forerunner
Cursory
quick, as a glance
Current
a running glow, as of water or electricity
Courser
a swift-running horse
Cursive
flowing writing
Corridor
a long, running hallway
Corsair
one who runs from the law, a pirate
Discourse
a long-running speech
Curriculum
the entire run of courses offered to a student