map key Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition noun. a guide that explains symbols on a map. Example Sentence The picture of a tree on the map key represented a forest. More Example Sentences You need the map key to read the map. Synonyms legend; guide; symbol key Antonyms door Hear It! Say It! Write It! map key Switch to cursive Start Share with your friends: