Generative AI refers to artificial intelligence systems capable of producing novel content, such as text, images, audio, or code, rather than merely analyzing or classifying existing data. Large Language Models (LLMs) are a class of Generative AI specifically trained on vast datasets of text and code, enabling them to understand, generate, and process human language with remarkable fluency. ChatGPT, developed by OpenAI, is a prominent LLM built upon the Transformer architecture, excelling in conversational AI and a wide range of text-based tasks. Its 'GPT' stands for Generative Pre-trained Transformer, signifying its ability to generate text based on patterns learned during its extensive pre-training.