Many discussions of "classes" in the 19th century and earlier are really referring to sets, or perhaps to a more ambiguous concept.

"In fashion, quality is sometimes an ambiguous concept," he said.

Executive privilege is one of the most ambiguous concepts in constitutional law.

It had its own bugeye, sure - privacy was an ambiguous concept anywhere in the Bill's domain.

While quality is an ambiguous concept, the focus should be on how to increase the value of health care products and services without raising the costs.

Public interest, however, is an ambiguous concept; its meaning changes with time and place.

The definition of executive privilege is one of the most ambiguous concepts in Constitutional law.

In public relations and communication science, it is one of the more ambiguous concepts in the field.

However, method is an ambiguous concept in language teaching, and has been used in many different ways.

Discussion question: In what way is justice an ambiguous concept?