The western part of the African continent, especially the countries bounded by and including Mauritania, Mali, and Niger in the north and Gabon in the south.
西非（非洲大陆西部，尤指北部的毛里塔尼亚、马里和尼日尔与南部的加蓬以及位于这些国家之间的各国）
Definition of West Africa in US English:
West Africa
proper nounwest ˈafrəkə
The western part of the African continent, especially the countries bounded by and including Mauritania, Mali, and Niger in the north and Gabon in the south.