Share 'Grounding and Centering'

As spiritual and magical beings,we hear the terms grounding and centering quite a bit. Are they the same,close to the same or different? For me they are different,as grounding means being here now and centering is being aware of myself and what is going on with me. Opinions? also how do you Ground and center? I ground by using the Celtic tree grounding.V arms out,feet in the ground. I center,by...