To synthesize means to combine separate pieces or ideas into something new and unified. When you synthesize information from three different books for a research report, you blend the ideas together, find connections, and create your own understanding that's more complete than any single source could provide.

Scientists synthesize compounds in laboratories by combining chemicals to create new substances. Some medicines, plastics, and fabrics are synthetic, meaning they were made by synthesis rather than found naturally. The word suggests active creation: you're taking ingredients or components and producing something that didn't exist before.

In writing and thinking, synthesis is a powerful skill. When you synthesize evidence for an argument, you weave together examples, facts, and reasoning into a convincing whole. A good book report synthesizes plot summary, character analysis, and personal reaction into a unified essay, not separate paragraphs stuck together.

The opposite of synthesis might be analysis, where you break something down into parts. Synthesis does the reverse: it builds up from parts into something new. A DJ synthesizes different musical elements into a new song. A chef synthesizes flavors and techniques from different cuisines to create an original dish.