Definition
The terminal of an electrical source (such as a battery or generator) from which conventional current flows out into the external circuit. It is the terminal at higher electrical potential relative to the negative terminal, and is typically marked with a plus (+) sign or red coloring.
Plain English
The plus side of a battery or power source. It is the point where current is considered to leave the battery and travel through the wires and equipment before returning to the minus side.
Context Anchor
Seen during battery installation, electrical troubleshooting, and any maintenance task involving aircraft power connections.
Derivation
From Latin positivus, meaning 'set down' or 'fixed.' In early electrical work, scientists arbitrarily assigned one terminal as 'positive' and the other as 'negative' to describe the direction of current flow. The label stuck even after we learned that electrons actually move the other way.
Why Pilots Care
Connecting power leads to the wrong terminal can reverse polarity, damaging avionics, tripping breakers, or creating fire hazards.
Intuition Check
Positive does not mean “good” or “safe” here; it means the plus side of an electrical circuit. Terminal does not mean an airport building here; it means a connection point for a wire or cable.
Example Sentence 1
Before installing the new battery, the mechanic verified that the red cable was attached to the positive terminal.
Example Sentence 2
Loose corrosion on the positive terminal caused intermittent power loss to the radios.