Description: The term ‘in domain’ refers to data or tasks that are similar to the training data used to develop a large language model (LLM). In this context, ‘in domain’ implies that the model is optimized to work with information that resembles what it has been exposed to during its training phase. This means that the model can generate more accurate and relevant responses when faced with queries that fall within its area of expertise. The ability of an LLM to operate ‘in domain’ is crucial for its performance, as models tend to be more effective in areas where they have deeper and more specific knowledge. For example, a model trained with domain-specific data, such as medical data, will be more competent in answering health-related questions than one trained with a more general dataset. The relevance of this concept lies in the need to adapt and fine-tune models for specific tasks, allowing developers to maximize the utility and accuracy of AI-based applications. In summary, ‘in domain’ is a key concept that underscores the importance of specialization in training large language models, directly affecting their ability to provide useful and accurate responses in specific contexts.