GMCs are so large that "local" ones can cover a significant fraction of a constellation; thus they are often referred to by the name of that constellation, e.g. the Orion Molecular Cloud (OMC) or the Taurus Molecular Cloud (TMC).
As GMC son tan grandes que as "locais" poden chegar a cubrir unha parte importante dunha constelación de tal xeito que son referidas a miúdo polo nome desa constelación, por exemplo, a Nube Molecular de Orión (OMC) ou a nube molecular Tauro (TMC).