Field buzzed with energy (5)
I believe the answer is:
range
'field' is the definition.
(I've seen this in other clues)
'buzzed with energy' is the wordplay.
'buzzed' becomes 'rang' (both can mean telephoned).
'with' means one lot of letters go next to another.
'energy' becomes 'e' (physics symbol as in E=mc2).
'rang'+'e'='RANGE'
(Other definitions for range that I've seen before include "specific category" , "Cut; cultivated plant" , "Extent - shooting area" , "Scope, extent" , "on which 'Dr Brewster Higley' felt at home?" .)