In French Horn how do you notate whether or not to put the hand in the bell?

[Pete]

Is there a word for putting your hand in the bell or taking your hand out of the bell, e.g. "con sordino"/"senza sordino" is for mute but I need to know the word for hand in bell, thanks.

 

[bka]

do you mean "stopped" like all the way in the bell, closing the horn?

you use a heavy + symbol over the note, and then a heavy O symbol over another note to undo it for unstopped (called "open").

you can also label it "stopped" and "open" especially to clarify if it stays stopped for several measures.

 

[Greg]

In proper playing technique, the hand is ALWAYS in the bell. There's no special term for it, because the practice is already implied.