RULES OF THUMB

Some of you have constantly asked me what's the meaning of "Rules of Thumbs".

Well, the thumb is that short, thick finger on your hand, the one that helps you hold things.

The noun “thumb” is used in a lot of expressions:
to give someone the thumbs up/down
to give someone approval/disapproval

Thumb Verbs
'Thumb is also used as a verb.
to thumb a ride (informal)
to hitchhike; to try to get a ride by standing on the road sticking out your thumb.

Thumb Idioms
Here are some idioms with thumb.
Can you guess their idiomatic meanings by thinking about their literal meanings?

To stick out like a sore thumb:
Betty sticks out like a sore thumb in that yellow dress. Everyone else is wearing blue.
(Betty looks very different from everyone else; she looks a little foolish.)

A green thumb:
He has a green thumb. He is good at making plants grow. Everything in his garden flourishes.

A Rule of Thumb is a practical rule - a rule of principles that provides guidance to appropriate behavior. A guideline.
“You should pay your best attention to the The Rules of Thumb listed in every issue of this Blog”.