What is 'Rigging

Hi, I was just wondering what exactly is 'Rigging a 3d model'? I tried google, and wikipedia, and Rigging seems to have many definitions, and I couldn't find much explaining what it means in 3D modeling contexts.
From context of what I did find (And hear others talking about) I could guess it has to do with modelers preparing a shape for animation, such as putting Bones in, nodes etc. Is this right?