A: How often should I take my kids to see a dentist?

    B: As a rule of thumb, children should see a dentist once a year.

    Note: This idiom refers to a means of estimation made according to a rough and ready practical rule, not based on science or exact measurement. It’s said to have derived from the belief that English law allowed a man to beat his wife with a stick so long as it was no thicker than his thumb. In 1782, judge Sir Francis Buller was reported as having made this legal ruling and in the following year James Gillray published a satirical cartoon attacking Buller and caricaturing him as “Judge Thumb.” The cartoon showed a man beating a fleeing woman and Buller carrying two bundles of sticks. The caption read, “thumbsticks — for family correction: warranted lawful!”