How did コンセント come to be used for an "electrical outlet"? Saw this on a charger I bought online and was really perplexed. What foreign word does it represent? "concentric"? What does that have to do with electrical outlet and where did it come from?

It is . Sometime around the 1920s, employees at created a device which consisted of a plug and outlet. This was called "concentric plug". Outlets without the plugs are now referred to as . Needless to say, English "concentric" does not make much sense.