An online micro-learning resource is a small, self-contained learning module that is delivered online and can be completed in a short amount of time. They are designed to deliver bite-sized units of information that can be quickly absorbed and retained by the learner. 

These resources provide quick and targeted learning experiences to learners who need to acquire new skills or knowledge in a time-efficient manner, and to support just-in-time learning needs. They are particularly useful for learners that need to learn on-the-go, as well as for those who prefer to learn in short bursts rather than in long, traditional sessions. Micro-learning is an effective approach to learning, as it allows learners to acquire new knowledge and skills in an interactive, fun way.