OPEN CENTER
In a BodyGraph, the open Center is white. Open Centers are neither empty or broken, nor do they need to be fixed. Open Centers are vulnerable to being conditioned.
When a person with an open Center meets someone who colors that Center in, they amplify as a response. If you have a Solar Plexus that is white and you meet someone who is in a bad mood and has that Center defined/colored in, then in meeting them you will take in and amplify their emotional wave. This is not a pleasant experience.
Metaphorically, you could say, that what is defined is the 'student' and what is open is the 'course' of study. (see Undefined)
Sometimes, an "open" center is used to refer specifically to a center that has no activations whatsoever.