IIC (or I2C) stands for InterIntegratedCircuit, also (and usually) pronounced EyeSquaredCee. The two is typically superscripted like the standard mathematical notation for exponentiation; WardsWiki doesn't allow us to write super or subscripts currently.
It is a 2-wire, clocked serial bus developed by PhilipsSemiconductor as an inexpensive, electronically simple way of communicating between the various ICs in a complex circuit.
It is enabled directly in a variety of MicroProcessors and MicroControllers, and a purpose-built controller, the PCF8584 (also by Philips).
It can be called a semi-synchronous, session-framed, bit-serial, byte-acknowledged protocol. It is the foundation for a widely used protocol convention, the AccessBus.
Using IIC, several small, inexpensive devices, each with its own control duties, can be chained together with a central controller. Quite useful in modular device systems.