21.   But how can the essence of complexity be captured and quantified in a precise definition that scientists can use?

22.   But it is a term whose precise definition is somewhat elusive.

23.   Electronic commerce still eludes precise definitions.

24.   It seems intuitively identifiable but strangely resistant to precise definition.

25.   No precise legal definition exists.

26.   Proximate causation is not a concept susceptible of precise definition.

27.   That debate boils down to what is a planet and what is not, a seemingly straightforward concept with no precise definition.

28.   The formal laws of land warfare are unclear about the precise definition of noncombatants in international conflicts.

29.   The term commonwealth has no precise definition in international law.

30.   There is no precise definition for a plateau de fruit de mer.