Plain English Meaning
A way of landing two airplanes at the same time on two runways that sit very close together. One airplane flies straight in to its runway. The other flies an approach that is angled slightly off to the side until it gets close to the airport, then turns to line up with its runway. The angle keeps the two airplanes safely apart while they are still in the clouds.
Full Definition
A type of simultaneous instrument approach procedure used at airports with closely spaced parallel runways that are too close together to permit standard simultaneous independent ILS approaches. One runway is served by a straight-in ILS approach, while the other is served by an offset approach (typically an with ) whose is angled a degrees away from the parallel . The offset reduces the of collision between on the two and allows to proceed simultaneously under () .