Is there an official, widely used subject classification? For a university project I want to classify authors according to the subjects/domains they frequently publish in. For this purpose I want to first establish a subject classification with the according hierarchies (for example, chemical engineering would be a sub-subject of physical sciences and engineering).

Instead of creating my own classification/hierarchy, I would like to use an official classification of subjects. Unfortunately, I have not been able to find one that is universally accepted.

What I did find are the classifications of different publishers, for example the subjects listed for ScienceDirect.

So my question is:

Is there any official, widely used and accepted subject classification?

One thing I'd like to add:
English is not my mother tongue so it might be entirely possible that I am just using the wrong words for doing the search. I’ve been looking for subject or domain classifications. Maybe there is an entirely different term for what I am actually looking for.
In addition to the ones @Coder suggests, perhaps the library classification systems:


Library of Congress
Dewey Decimal
Universal Decimal Classification


might be useful?

As @tonysdg says below, there are a variety of other system, too.