IP55 2 Gang 2 Way Weatherproof Switch

what does IP stand for:

The protection indicated by the first digit are:
0: Does not protect against any solid objects
1: Protects against objects less than 50mm diameter
2: Protects against foreign objects less than 12.5mm
3: Protects against foreign objects less than 2.5mm
4: Protects against foreign objects less than 1.0 mm
5: Protects against dust such that it will not affect the performance of the equipment
6: Totally dust tight.

The protection indicated by the second digit are:
0: Does not protect at all
1: Protects against vertically dripping water
2:-Protects against dripping water when tilted up to 15 degrees
3: Protects against spraying water
4: Protects against splashing water
5: Protects against jets of water
6: Protects against powerful jets of water
7: Protects against immersion in water to one metre for 30 minutes
8: Protects against continuous immersion in water (to a depth specified by the manufacturer). Weatherproof sockets are protected against the worst of weather conditions when they are IP55 or better.