I always think of grounding as being closely linked to mindfulness. It helps us to live in the present moment, fully in our body, and to deal constructively with what’s going on around (and within) us. Energetically, when we’re grounded, our consciousness and etheric/astral body are perfectly centred in our physical body and firmly anchored to the earth.
This doesn’t mean we can’t also be connected to Spirit at the same time. In fact if you’re going to do spiritual work, grounding yourself first is a very good idea. What we’re aiming for in the long run is to be grounded in our physical body, and still able to connect perfectly to our other bodies too – the emotional, mental and spiritual.