https://www.energy.gov/energysaver/heat-and-cool/heat-pump-s...
Geothermal works with either vertical holes in the ground or a big loop spread out horizontally. Neither one is very deep nor does it involve hot rocks.
Geothermal heat on the other hand is a wider term https://en.m.wikipedia.org/wiki/Geothermal_heating of which geothermal heat pumps (ground source heat pumps) https://en.m.wikipedia.org/wiki/Ground_source_heat_pump are just a subset.
https://www.energy.gov/energysaver/heat-and-cool/heat-pump-s...
Geothermal works with either vertical holes in the ground or a big loop spread out horizontally. Neither one is very deep nor does it involve hot rocks.