A Pivot

1. A thing on which something turns; specifically a metal pointed pin or short shaft in machinery, such as the end of an axle or spindle.
2. (figurative, by extension) Something or someone having a paramount significance in a certain situation.
3. Act of turning on one foot.
4. (military) The officer or soldier who simply turns in his place while the company or line moves around him in wheeling.
5. (roller derby) A player with responsibility for co-ordinating their team in a particular jam.
6. (computing) An element of a set to be sorted that is chosen as a midpoint, so as to divide the other elements into two groups to be dealt with recursively.
7. (computing) A pivot table.
8. (graphical user interface) Any of a row of captioned elements used to navigate to subpages, rather like tabs.
9. (mathematics) An element of a matrix that is used as a focus for row operations, such as dividing the row by the pivot, or adding multiples of the row to other rows making all other values in the pivot column 0.
10. (Canadian football) A quarterback.
11. (US, politics) A shift during a general election in a political candidate's messaging to reflect plans and values more moderate than those advocated during the primary.