What is the difference between a glassy, amorphous and a vitreous phase? I have been reading about some inorganic materials lately, and these three terms confuse me. If they all mean the same thing, would still one of them have preference over others?
After some reading I have decided to answer this question myself for anyone else with the same confusion. The info is from the downvoted answer of alphonse and the wiki-link, but with a better overview.


Both vitreous and glassy are amorphous. Amorhous is the broadest term to rule them all.


Some amorphous materials have a Glass Transition Temperature (GTT). Above this temperature the material becomes a viscous liquid. note that both below and above the GTT the material is amorphous.


An amorphous solid that has a GTT is called a glass.
The transition (heating) over the GTT results in a glassy phase.
The reverse transition (cooling) corresponding to the GTT is called vitrifcation. The result is a vitreous phase.


If I made mistakes please comment and I will update the answer.