In the context of artificial intelligence (AI), "training data" refers to the dataset used to teach or train an AI model. Think of training data as the educational material for AI, similar to textbooks for students. This data includes examples and information that help the AI understand and learn the specific task it is being developed for, whether it’s recognizing faces, translating languages, or predicting weather patterns.

Training data must be both diverse and comprehensive, covering a wide range of scenarios that the AI might encounter in the real world. For example, if you're training an AI to recognize cats in photographs, your training data should include images of different cat breeds, sizes, and colors, in various settings and positions. The quality and size of the training data greatly influence how well the AI model can perform its tasks. If the training data is too limited or biased, the AI model might struggle with accuracy or fail to generalize its learning to new situations. Therefore, selecting and preparing the right training data is a crucial step in building effective AI systems.