rat run

:  any of numerous rodents (Rattus and related genera) differing from the related mice especially by considerably larger size

:  any of various similar rodents

:  a contemptible person: such as

:  to catch or hunt rats

:  to work as a scab

:  to give (hair) the effect of greater quantity (as by use of a rat)

:  to go faster than a walk

:  to go steadily by springing steps so that both feet leave the ground for an instant in each step

:  to move at a fast gallop

:  an act or the action of running :  continued rapid movement

:  a quickened gallop

:  a migration of fish (as up or down a river) especially to spawn

:  being in a melted state

:  made from molten material :  cast in a mold

:  having made a migration or spawning run