Photon (noun)

1. The smallest unit of light and other forms of electromagnetic radiation.
2. A subatomic particle that is the quantum of electromagnetic energy and force carrier.

Origin:

The word photon was coined by the chemist gilbert n. lewis in 1926. it comes from the greek word "phōs" which means "light" and the word "-on" which is used to indicate a particle. it was first used to describe the smallest unit of light and other forms of electromagnetic radiation.

Examples:

1. The photon is the particle that makes up light and other forms of electromagnetic radiation.
2. Photons are massless particles that travel at the speed of light.
3. The energy of a photon is directly proportional to its frequency.
4. The process of photosynthesis in plants involves the absorption of photons by chlorophyll.
5. The study of photons is known as quantum electrodynamics.