National Learning Infrastructure Initiative:

"Learning objects are digital resources, modular in nature, that are used to support learning. They include, but are not limited to, simulations, electronic calculators, animations, tutorials, text entries, Web sites, bibliographies, audio and video clips, quizzes, photographs, illustrations, diagrams, graphs, maps, charts, and assessments. They vary in size, scope, and level of granularity ranging from a small chunk of instruction to a series of resources combined to provide a more complex learning experience. "
- posted by Yik Sheng @ 3:23 PM