  We exploit the close relationship between the Carroll and fracton/dipole
algebras, together with the method of coadjoint orbits, to define and classify
classical Carroll and fracton particles. This approach establishes a
Carroll/fracton correspondence and provides an answer to the question "What is
a fracton?".
  Under this correspondence, carrollian energy and center-of-mass correspond to
the fracton electric charge and dipole moment, respectively. Then immobile
massive Carroll particles correspond to the fracton monopoles, whereas certain
mobile Carroll particles ("centrons") correspond to fracton elementary dipoles.
We uncover various new massless carrollian/neutral fractonic particles, provide
an action in each case and relate them via a $GL(2,\mathbb{R})$ symmetry.
  We also comment on the limit from Poincar\'e particles, the relation to
(electric and magnetic) Carroll field theories, contrast Carroll boosts with
dipole transformations and highlight a generalisation to curved space ((A)dS
Carroll).
