A small marine fish of the herring family, often used for food. The fisherman caught a large net full of sprats to sell at the market.
A small or insignificant person. At only five feet tall, he was considered a sprat among his towering teammates.
Something of little value that is offered or risked in hope of obtaining something greater (often in the phrase "a sprat to catch a mackerel"). The free giveaway was just a sprat to catch a mackerel of long-term customers.