Now, if you're asking what the difference is between electronics (the noun) and electric (the adjective), one (electronics) refers to machines (or even parts of a machine) that use electricity, e.g. "Computers and DVD players are both electronics" The other (electric) is an adjective used to describe things that use electricity, e.g. "My electric razor is so much better than my old manual razor"
This is a FAQ by new students of electrical and electronics engineering.
My understanding is "electric" refers to flow of electricity due to energy conversion (from other forms of energy to electrical energy and vise versa)
On the other hand "electronic" refers to control of flow of electricity using some devices for achieving some desired objective (like amplifying, computation, tracking etc etc.)
I was going to answer this one before, but it seemed as though the OP had departed so I didn't bother. Anyway the history is basically as follows. Prior to the discovery of the electron tube most of the other common applications of electricity, like magnetism, motors, incandescent lighting, heating etc etc had already been discovered.
The electron tube opened up the way for new types of device including diode and triode tubes (commonly known as “valves”) which had characteristics quite similar to that of modern semiconductor diodes and transistors. This allowed the development of electron tube circuits that could perform more modern functions such as amplification and digital logic. These newer devices were termed “electron devices” as they worked on a new principle in which the electrons were made to leave the conductor, travel through a vacuum tube and do tricks for us. The resultant circuits built from these new devices were termed “electronic circuits” or just “electronics”.
Beginning around the 1960’s electron tube devices started to be replaced with the newer semiconductor diodes and transistors that superseded them. The name “electronics” stuck and was carried over to these newer devices and the circuits incorporating them. Initially these new semiconductor devices also carried the extra tag of “Solid State” electronics to distinguish them from the earlier vacuum tube devices that utilised a gas/plasm state. Over time the term “solid state” tended to get dropped (much in the same way as the word “motor” in “motor car” basically became redundant, now that they've all got a motor). So in essence electronics just refers to the circuits constructed from “vacuum tube electron devices” or the semiconductor devices that superseded them.