Idiom- Rule of thumb

Rule of thumb- Idiom of the day

Meaning:

• a principle that is kept to
• a guide that is based on practice rather than theory
• a general principle that comes through experience and not any scientific means
• a practical and approximate way

History:

This phrase has been believed to be  used since the 1600s and the origin is usually attributed to domestic violence, however, there is no proof of the theory. There was  believed to be a  law in England that allowed a man to beat his wife with a stick which was not thicker than his thumb. However, it has been found that such a law did not exist. Also, the phrase has been in use before this law was believed to have existed. The real origin of the phrase, therefore, is not known. 

Examples:

1. As a rule of thumb, I do not start any new projects on Mondays.
2. A good rule of thumb is to mix the batter immediately when the water starts to boil.
3. All students are asked to drink a glass of water every two hours as a rule of thumb.
4. Going by the rule of thumb, it would take two hours to reach Abu Dhabi.
5. As a rule of thumb, we never went camping near during the rains.