noun
full tank; filled up
Primarily used for gasoline or fuel tanks; implies the tank is completely filled.
ガソリンを満タンにしてください。
Please fill the tank up.
車の燃料が満タンになった。
The car's fuel tank is now full.
noun
full capacity; completely full
Extended use for batteries, containers, or any receptacle filled to its maximum capacity.
バッテリーが満タンになったら充電器を外してください。
Please disconnect the charger once the battery is fully charged.
この容器は満タンで10リットル入ります。
This container holds 10 liters when full.
満杯 is a more general term for 'full' or 'packed', used for spaces, schedules, or containers, while 満タン specifically emphasizes reaching the maximum capacity of a tank or receptacle, often with a nuance of 'topped off'.
Abbreviation of 満タンク (full tank), from 満 (full) + タンク (tank). The katakana portion reflects the loanword origin.