What do you call the part on the bow that you hold?
Take a look at the part of the stick you hold when playing your instrument. There is a sliding part used to adjust the tension of the hair ribbon. This part is generally referred to as the "bow frog." It allegedly gets its name from the amphibian it resembles.
The piece however has many names, such as "nut, "frosch" (German), "hausse" or "talon" (French), and "tallone" (Italian).