Is there an established distinction between a geyser and a cryovolcano in solar system bodies? Is there an established distinction between a geyser and a cryovolcano in the context of cold solar-system bodies such as the moons of Jupiter and Saturn, or Kuiper belt objects (e.g. Pluto)? 

Both can lead to spreading of new water across the surface, and both can result in plumes of water vapor above the surface. Do they have distinctly different mechanisms?

Or is it unclear or in a state of flux, a bit like the diagram in @zephyr's answer to Do astronomers generally agree that the distinction between comets and astroids is not so clear?
An educated guess: on Earth, the working fluid in a "geyser" is water, which remains a fluid more or less permanently after each eruption.  This means that geyser eruptions are not associated with buildup of new geological material around the geyser (apart from the much slower process of dissolved minerals accumulating as the water evaporates).

Contrariwise, on Earth, the working fluid in a "volcano" is molten rock, which solidifies after reaching the surface.  Each new eruption permanently deposits new solid material in the vicinity of the volcano.

If I were writing definitions, I would define a "cryovolcano" as a geological vent system where the working fluid is water, but where the environment is cold enough that the ejecta from eruptions accumulates in a permanent mountain of ice around the vent.