This is the winding of a transformer which is connected to the source of supply, normally the mains.
Turns of wire on the core, used to connect the input to the core.
That winding of a motor, transformer or other electrical device which is connected to the power source.
A winding connected to the voltage source or input.
In a multiple winding device it is the winding that is connected to the signal source. Only one winding can be designated as the primary. Figure of merit for an inductor. Measured as a ratio of the inductor reactance divided by the inductance resistance. This is a representation of the energy lost in an inductive device compared to the amount of energy contained in the electrical signal passed through it