For the man who has built a career on being difficult to define, the defining moment still lies ahead.

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The standards are notoriously difficult to define and seem to shift over time.

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Most observers believe that aggression will be left out of the court's jurisdiction because it is so difficult to define legally.

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However, the size of a country's domestic markets is a crude measure, not least because it is becoming difficult to define a domestic market.

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It is not difficult to define what a false statement means.

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Mr Spencer also says religion is "difficult to define and difficult to measure" - not unlike the feat of recording the lives of people in England and Wales.

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However, the health minister, Earl Howe, feared the move would be "counter-productive" because the concept of integrated care was "difficult to define" and risked being "too narrow" in some cases.

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In the end, victory may prove difficult to define.

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Even the great American research universities that have come closest to creating the core-and-cloud university of the future find it difficult to define the core and to manage relations with the cloud.

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It strikes me that trying to define where the front lines are might become a very difficult problem in wartime.

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