Though the technology has improved, the essential concept remains the same.

Discipline is an essential concept for performing any music.

What are the basic elements of this model which are embedded in its essential concepts and ideas?

Seeing Eye calls this intelligent disobedience, a difficult but essential concept for a guide dog to master.

In his theory he simplified the basic concepts, for instance heat is not an essential concept but a derived one.

Tribe members can also gather food, an essential concept.

Problems have arisen by separating the essential concept of the promise which rock is supposed to keep and the music that lies within.

In fact, the essential concepts of science are very often neither.

This is an absolutely essential concept that we should fix in our minds.

Without compromising the essential concept, I have made two major concessions in order to achieve a large measure of agreement.