Data source: Gina A. Zurlo and Todd M. Johnson, eds., World Christian Database (Leiden/Boston: Brill, 2024).
| Glossary item | Definition |
|---|---|
| ophthalmic mission | A foreign missionary society specializing in eye services. |
| opinion-makers | See decision-makers. |
| opportunity | In evangelization, the occasion, chance, time, or combinations of circumstances, times and places suitable or favorable for persons to hear and understand the gospel. |
| ordained minister | See minister. |
| order | See clerical order. |
| order, religious | See religious orders. |
| orders | The office and dignity of a person in the Christian ministry. |
| ordinand | A person in training for ordination. |
| ordinariates | (symbol O). In the Catholic Church, 6 countries have country-wide jurisdictions for Eastern-rite Catholics, termed ordinariates. |
| ordinary | In canon law, an ecclesiastic in exercise of the jurisdiction permanently annexed to his office; in the RC Church, the pope and all diocesan bishops, abbots, apostolic administrators or vicars, prelates and prefects: in Anglican usage, the bishop or archdeacon. |
| ordination | The act of admission into, or the status of being in, the Christian ministry. |
| ordination of women | See women, ordination of. |
| ordinations, annual | Total to the Catholic priesthood: (1974) 4,380 secular, 2,551 religious; (1975) 4,140 secular, 2,488 religious; (1991) 6,600 secular, 2,403 religious; (1996) 6,800 secular, 2,509 religious. |
| organic union | The goal of church union negotiations whereby 2 previously separate denominations become a single organically-administered new denomination. |
| organized Christianity | Christianity as formally organized into traditions, denominations, and councils. |
| organized congregation | See congregation. |
| organized religion | A religion as formally organized by subdivisions, schools, sects, denominations or other bodies or groupings requiring membership. |
| Oriental Catholics | Eastern-rite Catholics (qv) in communion with the See of Rome. |
| Oriental Jews | The third major group of Diaspora Jews, after Ashkenazis (German-rite) and Sefardis (Spanish-rite); sometimes treated as a sub-division of Sefardis; Arabicspeaking Jews from North Africa and the Middle East. |
| Oriental Orthodox | Christians of Pre-Chalcedonian/ Non- Chalcedonian/Monophysite tradition, of 5 major types: Armenian, Coptic, Ethiopian, Syrian, Syro-Malabarese. |
| Oriental Orthodox Churches Conference | First conference of Syrian, Armenian, Coptic, Ethiopian and Syro-Malabarese Orthodox churches, held in Addis Ababa 1965. |
| Oriental-rite Catholics | Eastern-rite Catholics (qv). |
| Orthodox | In 4 traditions: Eastern (Chalcedonian), Oriental (Pre-Chalcedonian, Non-Chalcedonian, Monophysite), Assyrian Church of the East (Nestorian), and non-historical Orthodox. |
| Orthodox pentecostals | Orthodox in the organized charismatic renewal, expressed in healings, tongues, prophesying, etc. |
| orthodoxy | Right teaching in Christian theology, as contrasted with heresy and heterodoxy. |
Data on 18 categories of religion, including non-religious, by country, province, and people.
Data on all religions, Christian activities, and trends.
Membership data, year begun, and rates of change.
Population and religion data on all major cities & provinces.
Detailed information covering religion, culture, and geography.
A repository of historical data, including a chronology of Christianity from the 1st to 21st centuries.