Seismology was developed on Earth and shaped our model of the Earth's interior over the twentieth century. With the exception of the Philae lander, all in situ extraterrestrial seismological effort to date was limited to other terrestrial planets. All have in common a rigid crust above a solid mantle. The coming years may see the installation of seismometers on Europa, Titan, and Enceladus, so it is necessary to adapt seismological concepts to the setting of worlds with global oceans covered in ice. Here we use waveform analyses to identify and classify wave types, developing a lexicon for icy ocean world seismology intended to be useful to both seismologists and planetary scientists. We use results from spectral‐element simulations of broadband seismic wavefields to adapt seismological concepts to icy ocean worlds. We present a concise naming scheme for seismic waves and an overview of the features of the seismic wavefield on Europa, Titan, Ganymede, and Enceladus. In close connection with geophysical interior models, we analyze simulated seismic measurements of Europa and Titan that might be used to constrain geochemical parameters governing the habitability of a sub‐ice ocean. Plain Language Summary Icy ocean worlds, like Europa or Titan harbor an ocean below a solid ice layer. This ocean may be habitable but is difficult to study from orbit. We demonstrated that surface‐installed seismometers are able to measure ice thickness and ocean depth directly and help constrain ocean temperature and chemistry, which are both critical for potential habitability. This paper tries to bridge the gap between methods of seismology on Earth and potential icy moon seismology by adapting common concepts to this setting. Using seismic wavefield simulations on high‐performance computers, we showcase a few tests for ice thickness, ocean depth, location of seismic events, and the existence of high‐pressure ice layers below an ocean. The paper focuses on Europa and Titan, with a more general description of Ganymede and Enceladus. The seismic waveform databases are made available to the seismological and planetary community to allow other researchers to build their own studies on icy ocean world seismology. Key Points Prepares for icy moon seismology by proposing a phase‐naming scheme Observation of a few magnitude 3 events allows estimates of ice thickness and ocean depth The existence of high‐pressure ice phases can be inferred from spectral analysis