| In electronics terminology, Hold Time is a parameter associated with the data input of a sequential device, such as a flip flop.
Sequential circuits rely on a clock signal in order to change state. In the case of a flip flop, for example, the data presented to the data input of the device will not be 'captured' until a clock transition occurs. To avoid metastability, the data presented to the input of the device must be stable when it is being captured. Hold Time is defined as the length of time that data must be stable after the active clock edge in order for that data to be captured cleanly. | 
