The only similarity is that they all have to do with the movement/transfer of heat.Conductionis the process by which heat transfers between bodies that are in physical contact with each other. Heat is transferred without the movement of individual particles.Convectionis the process by which heat rises and cold descends. The particles of the medium actually move during this process.Radiationis the process by which heat is transferred between bodies that are not in direct contact with each other by means of electromagnetic waves.also, conduction and convection are to do with particle movement where as radiation is to do with electromagnetic waves.They are similar as---All the three are ways in which heat is transmitted.Conduction---By direct contact.Convection---By currents(covection)Radiati