すなわち connects two expressions that refer to the same thing, providing a more precise, explanatory, or alternative way of saying something. Think of it as a formal way to say つまり. For example, you might state a fact and then clarify it, or give a category and then name specific examples.

This word is primarily used in written language, academic contexts, formal speeches, or news reports. In everyday conversation, つまり is far more common and sounds natural. Using すなわち in casual chat would sound stiff, like reading a textbook aloud.

When using it, place it between the two parts, often with a comma before it. The sentence structure can be: (statement A)。すなわち、(statement B)。Both A and B should logically refer to the same idea.