Organizations
- Oceanography Society, a non-profit society founded in 1988, based in Rockville, Maryland, U.S. and incorporated in the District of Columbia
- Theosophical Order of Service, an international organization founded in 1908 by Annie Besant, the second International President of the Theosophical Society
- Temple of Set, an initiatory occult society claiming to be the world's leading left-hand path religious organization; it professes Setian philosophy and magical practice
- Tennessee Ornithological Society
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