What are centers and what does defined/open mean?
9 bodygraph centers are energy hubs with specific functions: Head (inspiration), Ajna (mind), Throat (manifestation), G (identity), Heart (willpower), Sacral (life energy), Spleen (intuition), Solar Plexus (emotions), Root (pressure). Defined (colored) = stable, consistent energy. Open (white) = you amplify this energy from others, but it's inconsistent.
Calculate your Human Design chart for free at hdmatrix.pro.