Definition:Internal Group Direct Product/Also known as

Internal Group Direct Product: Also known as
Some authors refer to the internal group direct product $H_1 \times H_2$ as the normal product of $H_1$ by $H_2$.

Other sources use the term semidirect product.

Some authors call it just the group direct product, but it should not be confused with the external group direct product.

Although this is just a more specific example of the internal direct product of general algebraic structures, it is usually defined and treated separately because of its considerable conceptual importance.