Axis showing various frequencies of relevance inside a rotating star, notably the Lamb frequency for a wave of degree l denoted as S_l, the Brunt-Väisälä frequency N, the rotation frequency Ω, and the frequency due to Alfvén waves ω_A. The relevant frequency regimes for different types of waves are indicated, as well as the regimes where particular forces can (or cannot) be treated perturbatively in the computation of oscillation modes. Waves in the sub-inertial regime have spin parameter s ≡ 2Ω/ω >  1, while waves in the super-inertial regime are characterised by s <  1. The indicated frequencies change throughout the evolution of the star. The figure was inspired by the scheme in Mathis & de Brye (2011) and is adapted from the version in Aerts et al. (2019), by Clio Gielen.