This publication occupies an intermediate position between the "Biological Encyclopedic Dictionary" and the dictionary for teachers "Basic Biological Terms and Concepts." Unlike the Biological Encyclopedic Dictionary, it pays more attention to bioecology and less biochemistry. Since it does not describe the systematic categories of animals, plants, fungi and microorganisms, its volume is small. The dictionary contains more than 3,000 articles that explain over 4,000 biological terms and concepts with examples or notes and is designed for a wide range of readers.