The term "atomic furnace" refers to a device that can produce high temperatures through nuclear reactions. However, there are several other phrases that can be used as synonyms for this term. For instance, you could refer to this device as a nuclear furnace, a thermonuclear reactor, or a fusion reactor. These words all carry the same connotation of a device that uses atomic reactions to produce heat and energy, making them useful alternatives when discussing the topic. Other synonyms for atomic furnace might include plasma torches, tokamaks, or magnetic confinement devices, all of which refer to specific types of nuclear reactors or devices that utilize atomic processes to generate heat.