1, The full form of PHY is Physics. It’s used on Academic & Science ,Physics in Worldwide

Physics is the natural science that studies matter, its motion and behavior through space and time, and the related entities of energy and force. Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.

2, The full form of PHY is Physical Layer. It’s used on Computing ,Networking in Worldwide

The physical layer is the first and lowest layer of the Open System Interconnection Model (OSI Model.)

The physical layer (also known as layer 1) deals with bit-level transmission between different devices and supports electrical or mechanical interfaces connecting to the physical medium for synchronized communication.

This layer plays with most of the network’s physical connections—wireless transmission, cabling, cabling standards and types, connectors and types, network interface cards, and more —as per network requirements.

The physical layer does not deal with the actual physical medium (like copper, fiber, etc.)

3, The full form of PHY is Phetchabun Airport. It’s used on Transport & Travel ,Airport Codes in Thailand

Phetchabun Airport (IATA code: PHY, ICAO: VTPB) is an airport serving Phetchabun, a province in northern Thailand.