The term Artificial Intelligence (AI) was coined by John McCarthy in 1956. According to him AI is defined as "the science and engineering of making intelligent machines.“

The Merriam Webster's Collegiate Dictionary gives us the following two meanings for AI:

1 : the capability of a machine to imitate intelligent human behavior

2 : a branch of computer science dealing with the simulation of intelligent behavior in computers

After WWII, a number of people independently started to work on intelligent machines. The English mathematician Alan Turing may have been the first. He gave a lecture on it in 1947. He also may have been the first to decide that AI was best researched by programming computers rather than by building machines. By the late 1950s, there were many researchers on AI, and most of them were basing their work on programming computers.

Apps :

Speech recognition - Instruct computer using speech

Remote controlled surgical procedures - Using robotics and computer-based optical systems

Game playing - There is some AI in these machines , but they play well against humans (Ex: machines that can play master level chess)

Advanced weather modeling - Use trends and past models to predict the weather

Branches:

Pattern recognition

Search

Genetic Programming

Logical AI

Learning from experience

Planning

Common sense knowledge and reasoning