Definition 1 of 2
Plain English Meaning
Inside a battery, unwanted material grows between the plates and connects them, causing the cell to leak its own charge and weaken the battery.
Full Definition
A condition inside a lead-acid battery in which lead sulfate crystals build up between the positive and negative plates and form a conductive path that partially or fully short-circuits the cell. A bridged cell loses voltage, will not hold a charge properly, and reduces the overall output of the battery.
Context Anchor
Seen in aircraft electrical and avionics troubleshooting, especially when a meter or test unit is connected to a live circuit to read a signal.
Derivation
From the ordinary sense of a bridge connecting two separated things. In a battery the plates are meant to be electrically separated; when material grows across the gap it forms a 'bridge' between them, which is exactly what should not happen.
Why Pilots Care
A bridged cell quietly drains battery capacity and can leave the aircraft with less starting power or less emergency reserve than the gauge suggests. Recognising the symptom — a battery that will not hold a charge — leads to replacement before it causes a problem in flight.
Analogy
It is like looking through a window to see what is happening inside a room, instead of opening the door and changing what is happening in the room.
Intuition Check
Bridging does not mean building a physical bridge or simply jumping around a failed part. Here it means connecting across a circuit in a way that lets you read or use the signal with very little effect on that circuit.
Example Sentence 1
The mechanic suspected bridging in one of the cells after the battery repeatedly failed to hold a charge overnight.
Example Sentence 2
The finished part showed a resin-rich area where bridging had occurred, requiring a repair patch before the component could be returned to service.