Niger River Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition noun. a major river in West Africa flowing through several countries. Example Sentence The Niger River is the principal river of western Africa. More Example Sentences Many people live near the Niger River. Synonyms waterway; river; stream Antonyms capital of Washington Hear It! Say It! Write It! Niger River Switch to cursive Start Share with your friends: