In order to enable courseware reuse, learning platforms nowadays
require the materials to be decomposed into small independent
learning units. When trying to fulfill this need, authors face
the problem of not knowing how to determine suitable learning
objects in their content. What is the appropriate size of one
such object? The rather general and abstract definitions for
learning objects found in the literature are not very helpful
for answering this question. What authors need is an operational
definition, which can be directly applied to the learning
materials. This paper proposes such a set of formal yet
practical definitions by describing learning objects along their
contents and resource type and shows how these definitions are
used by our platform, SCORE
