Data source: Gina A. Zurlo and Todd M. Johnson, eds., World Christian Database (Leiden/Boston: Brill, 2025).
| Glossary item | Definition |
|---|---|
| inclusive membership | The total of a church’s or denomination’s affiliated Christians (qv) or church members, of all ages and varieties including children, infants and persons under instruction, also termed total Christian community. |
| income, average | See family income, national income per person. |
| incumbent | The holder of an ecclesiastical benefice (diocese, office, or, more usually, parish). |
| Independency | Congregationalism; A religious movement originating in England after AD 1600 asserting a congregation’s independence of higher ecclesiastical authority. |
| independency | The ecclesiastical position rejecting control of churches by centralized denominationalist headquarters; organizing churches and missions independent of historic Christianity. |
| independency, religious | A movement asserting independence of a previously recognized ecclesiastical authority, especially exemplified in the African indigenous churches (qv). |
| independent | Term for independent Evangelical churches with no denomination affiliation or ties. |
| Independent | Congregationalist. |
| Independent Charismatics | Members of the Pentecostal/Charismatic renewal characterized by the adjectives Independent, Post-denominationalist, and Neo-Apostolic. Similar to charismatics but unconnected with mainline Pentecostal or non-Pentecostal denominations. |
| Independents | Christians who identify as independent of the major Christian traditions (Orthodox, Catholic, Protestant). Independent of historic, organised, institutionalized and denominationalist Christianity. |
| Independents | One of Christianity’s 6 ecclesiastico-cultural megablocs, separated from, uninterested in, and independent of historic denominationalist Christianity (the other 5 megablocs). |
| in-depth evangelism | See Evangelism-in-Depth. |
| in-depth evangelism | The strategy of united programs of evangelism in a country or area; total mobilization evangelism, saturation evangelism, Evangelism-in-Depth, New Life for All, etc., stressing mobilization of all believers and their resources within the framework of church, reaching all unbelievers in the area, through every available means. |
| Index Librorum Prohibitorum | List published at Rome of prohibited books judged dangerous to faith or morals; created 1557, abolished 1965. |
| Indian indigenous churches | Denominations indigenous to, and started by, Indians. |
| indicator | Any descriptive property or variable, a measuring device. |
| indigenous | Originating or developing or produced naturally in a particular land or region or environment; not introduced directly or indirectly from the outside. |
| indigenous Christianity | In a particular region, that type of Christianity which, in contrast to imported or foreign types, is evolved or produced by populations indigenous to that region. |
| indigenous church | A locally-founded church, i.e. one originating within a country or race or people, or produced naturally by nationals of that country or members of that race or people, as opposed to a church of foreign or alien origin imported from abroad or introduced from outside. |
| indigenous evangelization | Spreading of the gospel among a non-Christian population by persons indigenous to that population. |
| indigenous media | See folk media. |
| indigenous religious institutes | In Catholic usage, locally-founded religious congregations of men or women began in mission fields. |
| indigenous,Third-World | Churches and Christians indigenous to the Third World. |
| indirect access | Access (qv) to Scripture but only through a near-scripture in a language in the same cluster. |
| individual | A person; the fundamental statistical unit used in demography. |
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.