A dimer is a molecule formed when two identical or similar smaller molecules, known as monomers, chemically bond together. This process can occur through various types of chemical reactions, such as covalent bonding. Dimers can be found in many natural and synthetic substances, including proteins and polymers. In chemistry, dimers play a significant role in understanding molecular interactions and properties. For example, in the case of proteins, dimers can influence biological functions and activities. Additionally, in the field of polymer science, dimers can serve as building blocks for larger, more complex structures.