A claim that a movement has been regulated to maintain accuracy across multiple physical orientations, such as dial up, dial down, and crown up, rather than just one resting position.
A watch movement runs at slightly different rates depending on its physical orientation, since gravity affects the balance wheel and escapement differently when the watch is lying flat versus standing on its side. Adjusting a movement to positions means a watchmaker has regulated it across several of these orientations, commonly five or six, so its accuracy holds up regardless of how the watch is resting or being worn.
The claim is usually stated as a specific number, such as adjusted to five positions, and was historically a significant selling point on vintage watches, particularly railroad-grade pocket watches where consistent accuracy in any position was a practical requirement rather than a luxury.
Gravity affects the balance wheel and escapement differently depending on orientation, so a movement that hasn't been adjusted for multiple positions may run at slightly different rates lying flat versus standing on its side.
Commonly five or six, though the exact number varies and is usually stated explicitly, such as adjusted to five positions.
It's historically most associated with vintage and railroad-grade pocket watches, where it was a practical necessity, though the same regulating principle still applies to high-grade modern movements.