SahelPronunciation: /səˈhɛl/Definition of Sahel a vast semi-arid region of North Africa, to the south of the Sahara, which forms a transitional zone at the south of the desert and comprises the northern part of the region known as Sudan. Derivatives SahelianPronunciation: /-ˈhiːlɪən/ adjective & noun Sahel in other Oxford dictionaries Definition of Sahel in the US English dictionary