The condition of a river with respect to the rate of its flow, as measured by the volume of water passing different cross sections in a given time, uniform régime being the condition when the flow is equal and uniform at all the cross sections.
"Regime theory" is a theory of the forming of channels in material carried by the streams. As used in this sense, the word "regime" applies only to streams that make at least part of their boundaries from their transported load and part of their transported load from their boundaries, carrying out the process at different places and times in any one stream in a balanced or alternating manner that prevents unlimited growth or removal of boundaries. A stream, river, or canal of this type is called a "regime stream, river, or canal." A regime channel is said to be "in regime" when it has achieved average equilibrium; that is, the average values of the quantities that constitute regime do not show a definite trend over a considerable period--generally of the order of a decade. In unspecialized use "regime" and "regimen" are synonyms.
The period during which you can call a specific set of FTAM functions; the regime determines the activities that can occur at a given time and therefore, creates the rules (protocols) for the FTAM state machine. (For example, the Data Transfer regime allows reading or writing of the file.) Regimes are nested.