A portmanteau of "j" and "imaginary" for the imaginary component of a complex number. This means the same thing as Imaginary Number, and typically this number would have an italicized i after it. In electrical engineering, the letter "i" has other and more apparent meanings, so to avoid confusion we pick the next letter, j.
Compare imaginary with jimaginary number Sheldon would use 1 + 2i.
Howard would use 1 + 2j.
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. Penguin Books,1992. p. 38)