Bug
Bug turns up in 2 fields: electricians, aviation. Here is what it means to the people in each one.
Bug in electricians
Split-bolt connector used to splice or tap heavy conductors, then wrapped in tape.
A bug is a split-bolt connector: a bolt with a slot through its shank and a nut that clamps two or more conductors together inside the slot. It is used for splices and taps on heavy wire such as service conductors and grounding electrode conductors, then wrapped in rubber and vinyl tape. Plain copper bugs are for copper only, while dual-rated versions, often packed with oxide inhibitor, handle aluminium and mixed connections.
"Tap the ground with a bug, tape it up good, and run it back to the water pipe clamp."
Bug in aviation
A small movable marker on the rim of a flight instrument dial.
A bug is a physical or digital index marker used by pilots to set reference values on instruments like the airspeed indicator, altimeter, or heading indicator. Crews slide or dial these markers to specific target numbers during a briefing, such as rotation speed or a minimum descent altitude. They provide a quick visual cue during high-workload phases of flight, eliminating the need to memorize exact numbers.
"Set the heading bug to 270 and make sure your airspeed bugs are set for a flaps-30 landing."