Stationary anchorage refers to a situation where the anchorage unit remains stable with minimal or no movement during orthodontic force application. In this context, the anchor teeth tip slightly rather than moving bodily because tipping requires less force and moment than bodily movement. This slight tipping maintains the overall position of the anchor unit effectively, providing a controlled resistance point for tooth movement. Complete immobility (no movement) is practically unachievable due to periodontal ligament elasticity. Therefore, minimal tipping is accepted as stationary anchorage in clinical orthodontics.

Reference: Proffit, Contemporary Orthodontics, 6th Edition.