A shared acronym that can mean Level of Development or Level of Detail. VDCForum uses the acronym only to mean Level of Development.
Level of Development is a framework used to describe the degree to which a model element has been developed so teams understand how much they can rely on it for design, coordination, fabrication, construction, and operations decisions. See vdcforum.org/lod
Level of Detail is a term used to describe how much geometric or visual detail appears in a model element.
In practice, Level of Development is sometimes confused with Level of Detail, so project teams should define which meaning they intend in the BIM execution documents.