Meat from two kings on river (4)
I believe the answer is:
pork
'meat' is the definition.
(pork is a kind of meat)
'two kings on river' is the wordplay.
'two kings' means two substitutions for 'king'.
'king' becomes 'r' (r is abbreviation for rex).
'king' becomes 'k' (abbreviation for king in chess).
'on' means one lot of letters go next to another.
'river' becomes 'Po River' (Italian river).
'r'+'k'='rk'
'rk' after 'po' is 'PORK'.
'from' acts as a link.
(Other definitions for pork that I've seen before include "Pigmeat" , "Pig flesh" , "Pig's flesh as food" , "Cassoulet ingredient" , "Pig meat" .)