A SCO (Sharable Content Object) is the atomic launchable unit defined by the SCORM specification. Each SCO is a self-contained piece of content — typically a web page or HTML5 module — that the LMS opens in a window and that communicates independently with the LMS run-time API to report its own completion, score, and session data. A single SCORM package can contain one or many SCOs, and the manifest (imsmanifest.xml) lists them along with any sequencing rules that govern the order in which the LMS presents them. The "shareable" in the name reflects the original goal: a SCO should be reusable across different LMS platforms without modification, because it adheres to the standard API contract. In practice, however, SCOs often contain LMS-specific assumptions or rely on JavaScript quirks that reduce their portability. For video-focused products a SCO is commonly the entire video lesson wrapped in a thin HTML shell that initialises the SCORM API, loads the video player, and reports completion when the player fires a completion event. One SCO per lesson is the simplest packaging approach; splitting a course into many SCOs enables finer-grained sequencing but multiplies the complexity of the manifest and the number of SCORM API sessions the LMS must manage.
