According to Nina on House of Anubis on Nickelodeon: the bottom of a chandelier
Not really, it was refering to what was in the chandelier, the relic. And so the relic was half a sphere so it would be basically a hemisphere.
A hemi- or demisphere.
After getting the relic go out of the attic go through the girls hall and go DOWNthe stairs. When you are down it should be laying near the wall on The floor. It looks like a little stick with a base with hirofliphics on it. SIBUNA!