Aspects of nature that vibrate at higher frequencies than we can perceive with our physical senses. Classically, the superior worlds are called "heavens, nirvana," etc.
"Whosoever wants to awaken the consciousness in the Superior Worlds must begin by awakening it in the here and now." - Samael Aun Weor, Fundamentals of Gnostic Education
"...what each soul is in the Superior Worlds is the exact result of the daily life that everyone of us lives in this valley of tears." - Samael Aun Weor, Tarot and Kabbalah