B2a surface that lies at an angle to the horizontal so that some points on it are higher than others: The roof is at a slope (= at an angle to a horizontal surface) of 30°.Slanting, sloping, leaning, tiltingB2(part of) the side of a hill or mountain: a ski/mountain slopeSnow had settled on some of the higher slopes.There's a very steep slope just before you reach the top of the mountain.There are some nice gentle(= not steep) slopes that we can ski down.Hills and mountains