Synthesis/ˈsɪnθəsɪs/ Definition 1 of 5Pro Tip 1/2Scientific Creation Used to explain how something new is made by combining things, especially in science. The synthesis of new medicine starts with extensive research. Pro Tip 2/2Not Just Physical Synthesis doesn't always mean tangible items; it can combine ideas or data too. His thesis proposed a synthesis of historical data and modern theory.