The balancing of mechanisms consists in distributing their moving masses, inertias, and elastic components in order to achieve key mechanical properties, such as the insensitivity of the mechanism to gravity and to the motions of its chassis, or the elimination of the shaking forces and moments exported onto their supporting structure. This article presents a new taxonomy of mechanism balancing that is structured into 15 distinct types. The proposed classification clarifies the concepts of « static » and « dynamic » balancing, and reveals unexplored aspects of balancing that are relevant to the design of mechanisms exposed to high inertial disturbances, such as the oscillators of marine clocks and mechanical wrist-watches. The chronometric precision of these time-bases that are composed of an inertial body – typically a balance wheel – and a restoring spring – typically a hairspring – is indeed affected by the movement of their chassis. The classification of various mechanical horological oscillators according the new taxonomy reveals their key mechanical properties. Seven mechanisms have been selected : the oscillator of Huygens’ pendulum clock, the oscillators of three of Harrison’s marine chronometers (H1, H3 and H4), and three flexure-based oscillators developed by Instant-Lab (EPFL) dedicated to the future replacement of the traditional balance springs: Quadrivot (1-Degree-of-Freedom (DoF) force balanced oscillator), Wattone (1-DoF inertially balanced oscillator) and Wattwins (2-DoF planar IsoSpring® inertially balanced oscillator).