Black Sabbath's first shoots (4)
I believe the answer is:
jets
'shoots' is the definition.
(both can mean sprays or spurts)
'black sabbath's first' is the wordplay.
'black' becomes 'jet' (jet black is a kind of black).
'sabbath's first' becomes 's' (jst letter of 'sabbath').
'jet'+'s'='JETS'
(Other definitions for jets that I've seen before include "Fast airplanes" , "Water spouts or fast planes" , "Aeroplanes - Sharks rivals in "West Side Story"" , "Rapid streams of liquid or gas" .)