Encyclopedias, Almanacs, Transcripts, and Maps
- Orbas
- Orchid Family (Orchidaceae)
- Orchid Family (Orchidaeceae)
- Orchis, Root of
- Order of Bards, Ovates & Druids
- Order of Elect Cohens
- Order of Napunsakäs in the West
- Order of New Templars
- Order of the Black Ram
- Order of the Cubic Stone
- Order of the Sacred Word
- Order of the Silver Star
- Order of the Star
- Order of the Star in the East
- Order of the Thelemic Golden Dawn
- Order of the White Rose
- Ordering Knowledge in the Medieval World
- Ordinal Number
- Ordinal Number
- Ordo Rosae Rubeae et Aureae Crucis (Order of Rose of Ruby and Cross of Gold)