oak tree Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition noun. a type of tree that is strong and tall. it has lobed leaves and produces acorns. Example Sentence Acorns fell off the oak tree. More Example Sentences An oak tree can live for many years. Synonyms quercus; hardwood Antonyms squirrel Hear It! Say It! Write It! oak tree Switch to cursive Start Share with your friends: