SCORM explained to teachers

The Content Aggregation Model defines a powerful model for breaking content into arbitrarily sized units of reuse. These units are called Sharable Content Objects (SCOs) and Assets.

In SCORM terminology:

Asset

An electronic representation of media, text, images, sound, web pages, assessment objects or any other pieces of data that can be delivered to a Web client

SCO (Sharable Content Object)

A SCO is a collection of one or more assets and other SCOs that
represents a logical unit of learning.

It is the smallest learning resource that can be tracked by a LMS (via javascripts functions included in SCORM). Single assets cannot be tracked by an LMS.

SCOs cannot launch another SCO as this is a proper function of the LMS .

Content Aggregation

It is an "aggregation map" of assets and SCOs that represents a learning unit (a module, a course, ...).

The definition of an SCO is deliberately vague; it can be a single web page or a web-based training module containing hundreds of pages, images and other assets. The definition of an SCO is left up to the content author. Each SCO should be universally reusable.