Intelligent agent is a term commonly used to refer to software applications that are designed to perform specific tasks autonomously or in collaboration with humans. There are several synonyms for this term, including cognitive agent, smart agent, expert system, intelligent assistant, virtual agent, and autonomous agent. A cognitive agent is a smart system that can learn and reason, while a smart agent is a system that can adapt to changing conditions. Expert systems are computer programs that use artificial intelligence techniques to simulate the problem-solving ability of a human expert. Intelligent assistants are software applications that provide customized support and assistance to users by leveraging artificial intelligence techniques. Virtual agents are digital entities that can perform tasks on behalf of humans in virtual environments. Lastly, autonomous agents are self-governing systems that can operate independently without human supervision.