A planet's Equilibrium Temperature (Teq or Planetary Equilibrium Temperature) is the Temperature it would have given its incoming Electromagnetic Radiation (i.e., from its host star) if it were a simple Black Body, thus not subject to Atmospheric Windows, internal heat sources, etc.
Sometimes the term is used taking Albedo into account as well, and perhaps sometimes including other factors. Some cited equivalent temperatures (sources vary):
|Venus||328K||730K||Due to Greenhouse Effect|
|55 Cancri e||1958K||1613K-2709K||Day/Night|
|GJ 1132 b||600K|
|GJ 1214 b||555K|