Perhaps you're thinking of the phrase, "rule of thumb".
what does the phrase rule of thumb mean
The phrase is "to thumb ones nose at".
"Looks out of place" or "stands out like a sore thumb."
This phrase could have a couple of different meanings, but if "corto" is used as an adjective, it means "and short," as in the end of the phrase "his thumb is wide and short."
Rule of thumb refers to shortcuts to solutions to new problems that resemble problems previously solved by experienced workers.
The phrase "under my thumb" means to have control or dominance over someone or something, often in a manipulative or oppressive way. It can imply a power dynamic where one person is exerting authority or influence over another.
Showing only your thumb and small finger typically means "I love you" in American Sign Language.
A single action revolver, like the one shown above. The hammer must be cocked with the thumb before firing.
If you mean what is the "Rule of Thumb" it is an old law that states a man may beat his wife with a switch, (branch, stick), no bigger around than his "thumb". And we think we are civilized!?! This is completely wrong. There has never been any such law. The urban legend stems from a court case (not a law) in which the phrase "rule of thumb" never even appears. The judge only mentions that "moderate chastisement" of a wife by her husband is not criminal. Not at all excusable, and the judge was publicly excoriated for his ruling at the time. But this is not the origin of the "rule of thumb." The phrase "rule of thumb" comes from woodworkers using the length of their thumbs for measuring instead of using rulers, and it has been in use at least since the 1600s, long before the supposed "law" about wife-beating. A "rule of thumb" is a convenient approximation.
"The thumb" is an English equivalent of the Italian phrase il pollice.Specifically, the masculine singular definite article ilmeans "the." The masculine noun pollice means "thumb." The pronunciation is "eel POHL-lee-tcheh."
This is an urban legend. There was no such law. The phrase "rule of thumb" comes, rather, from the time-honored practice of using the thumb to make rough measurements (think "rule" as in "ruler"). In some languages, in fact, the word for "inch" is the same as the word for "thumb" (e.g., French pouce) or is derived from it (e.g. Spanish plugada, from pulgar).
The phrase "sore thumb" is often used to describe something that stands out or is easily noticed, like a thumb that is sore and therefore prominent. So, in that sense, yes, sore thumbs really do stick out.