What are the opposite words for by product?

The concept of "by-product" implies a secondary or incidental outcome of a process or action. Antonyms for this term might include "primary" or "direct product," implying a more intentional or deliberate output. Alternatively, "standalone product" or "core product" could be used to describe a primary focus or emphasis, rather than a supplementary or additional result. Additionally, "mainstream product" or "core offering" might suggest a primary or central product, rather than a marginal or auxiliary one. Ultimately, the choice of antonym depends on the context and intended meaning, but a range of possibilities exists for emphasizing a different aspect of a product or outcome.