A split where there is one pin missing between those left. For example, the 2-7, 3-10, 4-5, 5-6 splits.

The 2-7 or 3-10 split.

A split that can be converted into a spare, with the ball fitting between the pins. Examples include the 3-10 and the 2-7.

The 3-10 or 2-7.