GPT stands for "Generative Pre-trained Transformer", which is a type of artificial intelligence language model developed by OpenAI. It is pre-trained using a massive dataset of text, and can be fine-tuned on specific tasks such as language translation, summarization, question-answering, and text generation.
When used in a chatbot, GPT can generate human-like responses to user inputs based on previous conversations. This allows for a more natural and engaging conversation experience compared to traditional rule-based chatbots where responses are limited to pre-defined scripts.