Thumb

 
בֹּהֶן Strong’s #931 bohen

And he slew it; and Moses took of the blood thereof, and put it upon the tip of Aaron’s right ear, and upon the thumb of his right hand, and upon the great toe of his right foot.

Leviticus 8:23

https://biblehub.com/hebrew/931.htm

The thumb was identified as the “builder,” because of its need for “work” or “building.” This Hebrew word is not only related to the idea of building, but the word bohen itself is related to the Hebrew word meaning “to build,” banah (Strongs #1129)