lichens Get Printable Handwriting Hear It! Say It! Write It! Learn It! Spelling Test Definition plural noun. a type of organism formed from fungi and algae living together. Example Sentence The tree was covered in lichens. More Example Sentences Some lichens can survive in harsh places. Synonyms moss; algae; fungi Antonyms cat Hear It! Say It! Write It! lichens Switch to cursive Start Share with your friends: