thermodynamics?
Radiative heat transfer, or simply: radiation. As opposed to conduction and convection.
Heat travels by conduction by directly touching another object, absorbing its energy.
this source is sun
Heat travels in all of these ways.
Sunlight
Heat travels through empty spaces by radiation.
Heat travels through empty spaces by radiation.
It travels by conduction.
It may be called conduction, or heat transfer since heat only travels from an object to another if it contains a lower amount of heat.
thermal heat
If you are talking about heat transfer, these are both methods. Conduction is when something is touching a heat source, and so it starts to heat up. Convection is when heat travels upwards because it is lighter than cool air. I guess the similarity is they are both methods of heat transfer.
The definition of thermal conduction is heat transfer. Thermal conduction is when heat is transferred from one source to another.