Artificial Intelligence (AI) refers to the simulation of human intelligence in machines that are programmed to think and learn like humans. It encompasses a wide range of technologies and techniques, from basic rule-based systems to advanced neural networks and machine learning algorithms.

Key components of AI include:
1. **Machine Learning (ML)**: Algorithms that allow computers to learn from and make decisions or predictions based on data.
2. **Natural Language Processing (NLP)**: Enables computers to understand, interpret, and generate human language.
3. **Computer Vision**: Gives machines the ability to interpret visual information from the world, enabling tasks like object recognition and image analysis.
4. **Robotics**: Combines AI with mechanical systems to create robots capable of performing tasks in the physical world.

AI applications are diverse and expanding rapidly across industries such as healthcare, finance, transportation, and entertainment. Some examples include virtual assistants like Siri and Alexa, autonomous vehicles, recommendation systems (e.g., Netflix), and medical diagnosis systems.

Ethical considerations surrounding AI include issues of bias in algorithms, job displacement due to automation, and privacy concerns related to data collection and usage. As AI continues to evolve, ongoing discussions are crucial to ensure its responsible and beneficial integration into society.