This is a spare left when two or more pins remain standing, but with a gap between them. Spares are naturally a little harder to make (since you need to put the ball between two pins, or slide one pin over into another - see picture) and bowlers don't like to leave a split. While most of them are makeable (if you are accurate and know a good spare
system) the dreaded back row splits (e.g. 7-10, 8-10) are pretty much impossible. A special kind of split is the washout, where the headpin remains standing as the ball hooks by it. It is common to draw a circle round the pin-count on the score sheet to indicate that it was a split.