Definition of spillover

The word "spillover" originated in the 16th century, derived from the verb "spill," meaning to cause liquid to flow out of a container. Originally, "spillover" referred to the liquid that spilled out, but it evolved to describe anything that extends beyond its intended boundaries. This broader meaning likely arose from the visual imagery of liquid spilling over the edge of a container, representing an overflow or excess. By the 19th century, "spillover" was used to describe things like effects spreading beyond their original context, like the spillover of emotions or the spillover of economic activity.