A photon is a fundamental particle of light and is considered to be both a particle and a wave. It exhibits properties of both particles and waves, which is known as wave-particle duality.
From a particle perspective, a photon can be thought of as a discrete bundle of energy that carries electromagnetic radiation. Photons are massless and travel at the speed of light in a vacuum.
From a wave perspective, photons exhibit wave-like behavior, as described by the principles of electromagnetic waves. They have a wavelength and frequency associated with them, and they can interfere with other photons in a manner similar to how waves interfere with each other.
However, it is important to note that a photon is not a wave in a medium like a water wave. Unlike water waves that require a medium (such as water) to propagate, photons can travel through a vacuum without the need for a material medium. Photons are the fundamental units of electromagnetic radiation, which includes not only visible light but also other forms of electromagnetic waves such as radio waves, microwaves, infrared, ultraviolet, X-rays, and gamma rays.
In summary, a photon is considered both a particle and a wave, displaying properties of both. It is not a wave in a medium like a water wave, but rather a quantum of electromagnetic radiation.