Flux
The physical dose quantity flux indicates the flow per unit of time (t) of particles or otherwise. The name is derived from the Latijn word fluxus, meaning "flow". The corresponding unit is per second (s-1).The quantity flux density (commonly denoted by the Greek letter φ) is the flow per unit of time (t) and per unit of area (A). The corresponding unit is s-1·m-2.
From the definitions it follows that fluence rate = flux density.