Meaning A rough estimate.
Usage Worldwide.
Example
- I've no tape measure with me but I'd say, as a rule of thumb, that building is twelve metres high.
Pronunciation
Idiom
Rule of thumb
What does "Rule of thumb" mean?
A rough estimate.
Rule of thumb
Britain, 1600s. Not, as is often thought, derived from the size of stick a man was permitted to beat his wife with.