GlossaryAll | # A B C D E F G H I J K L M N O P Q R S T U V W X Y Z There are currently 3 names in this directory beginning with the letter J.JacketA covering applied over primary insulation, braids, shields, cable components or over the cable itself. Jumper A short length of conductor used to make a temporary connection between terminals, around a break in a circuit or around an instrument.Junction A point in a circuit where two or more wires are connected.