This idiom refers to a small, insignificant contribution or amount compared to what is needed or expected. It suggests that the effort, resource, or impact is minimal in the context of a larger problem or goal, often implying inadequacy or futility. The phrase is used in discussions of charity, progress, or resources to highlight scale disparities.

The phrase comes from the Bible, specifically Isaiah 40:15 (King James Version, 1611): ‘Behold, the nations are as a drop of a bucket, and are counted as the small dust of the balance.’ The imagery evokes a single drop of water in a large bucket, emphasizing insignificance. By the 19th century, it was common in English, with Charles Dickens using it in *A Christmas Carol* (1843) to describe Scrooge’s meager charity. Its secular use grew in American English, particularly in discussions of economics and philanthropy.