A measure of how well a load is matched to a transmission line✓Bonne réponse
The ratio of amplifier power output to input
The transmitter efficiency ratio
An indication of the quality of your station’s ground connection
Explication
SWR compares the peak and minimum voltages of the standing wave that appears when part of the forward power is reflected by a mismatched load, so it is a direct measure of how well the load matches the line. A perfect match gives 1:1 and reflects nothing.