The "electroweak force" is not considered a separate fundamental force but rather a unification of two fundamental forces: electromagnetism and the weak nuclear force. In particle physics, these forces were initially observed as separate phenomena, but through theoretical developments and experimental evidence, it was realized that they are different manifestations of a single unified force at high energies.
The electroweak unification is described by the electroweak theory, which combines electromagnetism (described by quantum electrodynamics or QED) with the weak nuclear force (described by the theory of weak interactions). At low energies, where we typically observe everyday phenomena, these forces appear distinct and can be treated separately. However, at extremely high energies, such as those present in the early universe or in particle accelerators, the electroweak force becomes apparent.
The concept of fundamental forces in physics is based on the idea that different forces can be described by distinct theories and have their own characteristic behavior and exchange particles. The four fundamental forces known in modern physics are gravity, electromagnetism, the weak nuclear force, and the strong nuclear force. While the electroweak force is a unification of two of these forces, it is not considered a separate fundamental force on its own.