The phrase "side gills" refers to the breathing holes that some animals have on the sides of their bodies. These openings help them take in oxygen from the water and are often found on creatures like fish or certain insects. Full definition
The profile is accented by the black 20 - inch wheels and signature M side gills on the front fenders. (automobilemag.com)
Along with the BMW kidney grille, door handles and side gills in black chrome and the carbon - fiber exterior mirror caps, they accentuate the extraordinarily sporty and powerful presence of the car. (press.bmwgroup.com)
The new side gills not only look good, but also serve to extract air pressure out from the front wheel arches. (drivemag.com)