Complex sentence: The martial art of wielding the jō is called "jōjutsu" or "jōdō"; "aiki-jō" is a set of techniques in aikido which uses the jō to illustrate aikido's principles with a weapon.
Split into simpler sentences: The martial art of wielding the jō is called "jōjutsu" or "jōdō". Also, "aiki-jō" is a set of techniques in aikido which uses the jō to illustrate aikido's principles with a weapon.