sprat
Concise Oxford English Dictionary © 2008 Oxford University Press:
sprat/sprat/
▶noun a small marine fish of the herring family, caught for food and fish products. [Sprattus sprattus (Europe) and other species.]
■ informal any small sea fish.
– phrases
a sprat to catch a mackerel Brit. a small outlay or risk ventured in the hope of a significant return.
a sprat to catch a mackerel Brit. a small outlay or risk ventured in the hope of a significant return.
– origin C16: var. of OE sprot, of unknown origin.
'sprat' also found in these Oxford entries:

