A metaphor is a way of using language which describes something by indirectly comparing it to something else with similar characteristics. For example, you might say an academic 'attacks' or 'demolishes' someone's theory or argument, just as an army can attack an enemy or workers can demolish a building.

If a metaphor is used so often that the original force of the comparison is lost then it may be called an idiom. For example, people often use the idiom 'I'm snowed under with work at the moment'. Originally this was a metaphor based on the idea of a great deal of work having the characteristics of 'snow' (deep, overwhelming everything else and making movement difficult). However, this expression has been used so frequently that it no longer gives people a mental picture of snow.

Look at these extracts from lectures where the speakers use such metaphors and idioms.

• • 'Critics opposed to D.H. Lawrence attacked his novels on various grounds... Lawrence's critics were united on what they saw as several serious problems.'
• • 'In the last two poems we see the poet becoming increasing detached from the material world, retreating [going back] more into his own mind than before.'
• • 'Parents and teachers need to maintain a united front [remain united in their opinions and agree on how to act] on the question of bad conduct at school.'
• • 'It's useful at the present time to look at Japan experience in the battle against air pollution, and it's a battle no nation can afford to lose.'
• • 'Lawsuits can certainly affect the value of a company, and firms need strategies to combat the onslaught [a very powerful attack] of lawsuits.'
• • 'In the last ten years or so, children have been bombarded with [forced to experience, subjected to] increasing amounts of violence in the media.'