Hexagram
A hexagram in the I Ching context is a 6-line figure (each yin/broken or yang/continuous) — total 64 possible hexagrams. Each one has name, judgment, image and changing lines, interpreted as oracle. In sacred geometry, "hexagram" also means the six-pointed star (Star of David, Seal of Solomon).
I Ching reading
Hexagrams read from bottom to top. Each line of the upper trigram interacts with the corresponding line of the lower. Lines "changing" produce a derivative hexagram.