The word "spank" refers to a physical action where someone strikes another person (typically a child) on the buttocks with an open hand as a form of punishment or discipline. It can also be used more generally to describe a playful or light smack on the bottom. The context in which "spank" is used can vary from strict disciplinary action to playful interaction.
The word "spank" likely comes from the Middle Dutch word "spanken," which means "to strike" or "to hit." The usage of the term in English can be traced back to the early 19th century, where it became associated with a specific form of corporal punishment.