What's the meaning of the term "State of the Art" and why is it call that way?

Answer 1

From wikipedia:

The state of the art is the highest level of development, as of a device, technique, or scientific field, achieved at a particular time.

The earliest known usage of the term "state of the art" dates back to 1910 from an engineering manual by H.H. Suplee titled Gas Turbine. It reads, "In the present state of the art this is all that can be done."