Definition of sprats:
(n) :
Any of various small, herring-like, marine fish in the genus Sprattus, in the family Clupeidae.
(n) :
Any of various similar fish of other genera.
(n) :
(by extension) Anything petty or insignificant.
(n) :
(UK, slang, obsolete) A sixpence.
(v) :
(transitive, historical) To manure (land) with sprats (the fish).