Note, explosive danger surrounds it (7)
I believe the answer is:
grenade
'note' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'explosive danger surrounds it' is the wordplay.
'explosive' is an anagram indicator.
'surrounds' indicates putting letters inside.
'it' becomes 'e' ('e' can mean 'electronic' which is similar to 'IT').
'danger' with letters rearranged gives 'grnade'.
'grnade' enclosing 'e' is 'GRENADE'.
Can you help me to learn more?
(Other definitions for grenade that I've seen before include "Bomb with a pin" , "Angered (anag)" , "Small bomb thrown by hand" , "Hand-thrown bomb" , "Hand-thrown explosive" .)