Definition of rule of thumb in English:

rule of thumb

phrase

  • A broadly accurate guide or principle, based on practice rather than theory.

    ‘a useful rule of thumb is that about ten hours will be needed to analyse each hour of recorded data’
    • ‘This is a good rule of thumb, and the first principle we use in evaluating potential home remedies.’
    • ‘The rule of thumb usually is to have three days of food and water and whatever essentials you might have.’
    • ‘Observation of individuals shows that people are much more likely to use rules of thumb when making complex decisions.’
    • ‘The general rules of thumb for a good private detective, Eddie said, are to be able to blend in, to act normally and be discreet.’
    • ‘As a rough rule of thumb, the best rates are available either over the internet or from some of the aggressive building societies.’
    • ‘Given that forecasts were so inaccurate, I thought it might be preferable to rely on projections based on simple rules of thumb.’
    • ‘As a rule of thumb, allow one houseplant per 100 square feet of living area.’
    • ‘A good rule of thumb would be to use colors based upon the type of effect you're trying to achieve.’
    • ‘I want to suggest that this is in fact a rather useful rule of thumb for linguists and philologists.’
    • ‘A widely adopted rule of thumb in crystallisation theory is that better crystals can be obtained using programmed cooling.’

Pronunciation

rule of thumb

/ˌruːl əv ˈθʌm/