Mac
Definition 1 of 5
Pro Tip 1/2
British Origin
The term 'mac' for raincoat comes from the UK, it's less common in other English-speaking countries. When in London, I bought a new mac for the unpredictable weather.
Pro Tip 2/2
Weather-Specific
Use 'mac' when discussing attire suitable for rainy, wet conditions. Check the forecast before you leave, you may need your mac.