Genealogy Glossary: A-Z of Terms Every Family Historian Should Know

Abstract - A condensed summary of the key facts in an original record (e.g. a will), without copying it word for word. Useful for filing in research notes.

Adoption (ADOP) - A legal parent-child relationship that is not biological. Recorded in GEDCOM as ADOP under the individual.

Affidavit - A sworn written statement, often used as evidence in immigration, naturalisation or marriage records.

Ahnentafel - German for "ancestor table". A numbering system (also called the Sosa-Stradonitz system) that gives every direct ancestor a unique number: you are 1, your father 2, your mother 3, paternal grandfather 4, and so on. Father of person *n* is *2n*; mother is *2n+1*.

Ancestor - A direct lineal forebear: parent, grandparent, great-grandparent, etc. Distinct from "relative", which includes siblings, cousins, etc.

Ancestry - The collective set of a person's ancestors. Also a brand name (Ancestry.com).

Archive - A physical or digital repository of original historical records. National, county, parish and university archives are the primary destinations for serious record research.

Banns - Public announcement of an upcoming marriage, traditionally read in church on three successive Sundays. Recorded in parish registers.

Baptism (BAPM) - Religious ceremony admitting a person (usually an infant) into the Christian church. Often the earliest written record of a person's existence.

Bigamy - Marriage to a second spouse while the first is still alive and undivorced. Surfaces in records as overlapping marriages or surprise children.

BMD - Birth, Marriage and Death. The three vital records that anchor most genealogical research.

BNF - Bibliothèque nationale de France; the French national library, key archive for French research.

Burial (BURI) - Record of interment, often in a parish register or cemetery archive.

Census - A periodic count of the population. UK censuses ran every 10 years from 1841 (released after a 100-year embargo); US censuses every 10 years from 1790. Censuses are the backbone of 19th and 20th century genealogy.

Christening - Synonym for baptism (BAPM in GEDCOM).

Civil registration - State-run recording of births, marriages and deaths. Began in England and Wales in 1837, Scotland in 1855, Ireland (all events) in 1864.

cM (centiMorgan) - Unit measuring shared DNA between two people. The Shared cM Project gives expected ranges for each relationship type.

Collateral relative - A relative not in your direct line - siblings, cousins, aunts, uncles. Researching collaterals is often how brick walls fall.

Common ancestor - The most recent person from whom two or more people both descend. Used to define cousin relationships and shared-DNA expectations.

Cousin (1st, 2nd, etc.) - Two people sharing a common ancestor. First cousins share grandparents; second cousins share great-grandparents. "Once removed" means a generation difference.

Descendant - A direct lineal heir: child, grandchild, great-grandchild, etc.

DNA match - Another person with whom you share a measurable amount of autosomal DNA, suggesting a relatively recent common ancestor.

Direct ancestor - A parent, grandparent or other ancestor in your direct line of descent. Distinct from collaterals.

Endogamy - Marriage within a closed community over many generations (e.g. Ashkenazi Jews, certain isolated villages, royal families). It produces inflated shared-cM values that make DNA cousin estimates unreliable without correction.

Enumeration district - A geographic subdivision used to organise census-taking. Useful when locating a known address in census records.

FAM (family record) - The GEDCOM record type that links spouses to each other and to their children. Sits alongside INDI (individual) records.

Family group sheet - A one-page summary of a family unit: parents, children, vital dates, sources. Standard worksheet for organising research.

FamilySearch - Free genealogy site operated by The Church of Jesus Christ of Latter-day Saints. Massive collection of digitised records and a single shared world tree.

FHS / FHL - Family History Society / Family History Library. Local volunteer societies (FHS) and the LDS Church's flagship genealogy library in Salt Lake City (FHL).

GEDCOM - GEnealogical Data COMmunication. The universal text-based file format for exchanging family-tree data between programs. Versions 5.5, 5.5.1 and 7 are in current use.

GEDCOM-X - A modern JSON/XML-based successor to GEDCOM developed by FamilySearch. Not yet widely adopted by desktop programs.

Generation - One step in a line of descent. Genealogists usually count 25-30 years per generation as a rough average.

GPS (Genealogical Proof Standard) - A five-element framework for what counts as a sufficiently-proven conclusion: thorough search, complete citation, careful analysis, conflict resolution, and a soundly written conclusion.

Half sibling - Two people sharing one parent rather than both. They share roughly half the DNA of full siblings.

Headstone - Gravestone inscription. Often the only surviving record of a death date or maiden name.

INDI (individual record) - The GEDCOM record type representing a single person.

Illegitimate - Born outside marriage. In historical records, often noted with stigmatising language. Modern genealogy treats illegitimacy neutrally.

IPM (Inquisition Post Mortem) - English/Welsh medieval and early-modern record of a tenant-in-chief's landholdings on death. Vital source for pre-parish-register research.

Julian calendar - The pre-1582 calendar still used in some countries until much later (Britain switched in 1752). Dates in this period need careful conversion to Gregorian.

Kinship - The exact relationship between two people in a tree. Calculated by finding their most recent common ancestor and counting generations to each.

Latter-day Saints (LDS) - The Church of Jesus Christ of Latter-day Saints, which operates FamilySearch and a global network of family history centres.

Lineage - A line of descent traced from a specific ancestor.

Maiden name - A woman's surname before marriage. In historical records often the most reliable way to disambiguate her.

Marriage (MARR) - The GEDCOM event tag for a marriage.

Migration - Movement of an individual or family between locations. Mapped chronologically, migration patterns reveal opportunity, hardship and chain-migration through extended family.

mtDNA (mitochondrial DNA) - DNA passed from mother to all children. Tracks the direct maternal line back many generations but mutates slowly.

Naturalisation - The legal process by which an immigrant becomes a citizen. Records often capture date of arrival, port and previous nationality.

NPE (non-paternity event) - A break in the biological paternal line - adoption, illegitimacy, misattributed paternity. Often surfaces unexpectedly in DNA testing.

Obituary - Death notice in a newspaper. Frequently contains relationships, residences, occupation and cause of death not found elsewhere.

One-name study - Research project covering every occurrence of a single surname, regardless of relation. Useful for surname distribution analysis.

Parish register - The handwritten record kept by a parish church recording baptisms, marriages and burials. The principal pre-civil-registration source in many countries.

Pedigree - A diagram or list of a person's ancestors.

Probate - The legal process of administering a deceased person's estate. Probate records (wills, inventories, letters of administration) are rich genealogical sources.

Relationship - The exact connection between two people in a tree (e.g. "second cousin once removed").

Relative - Anyone genealogically connected, ancestor or collateral. Distinct from "ancestor".

Sosa number - The Ahnentafel number assigned to each direct ancestor. See *Ahnentafel*.

Source - A document, person, website or publication providing evidence for a fact. Every fact should have at least one source.

Source citation - The formatted reference to a source, in enough detail that another researcher could locate it.

Surname - Family name. Patronymic (Anderson = "son of Anders"), occupational (Smith), locational (Lincoln) and descriptive (Black) are the four main origins.

Surname distribution - The geographic spread of a surname. Reveals likely places of origin and migration patterns.

Transcription - A typed copy of a handwritten original record. Always cite the *original* where possible, not just the transcription, since transcriptions introduce errors.

Tree - The hierarchical structure of an individual's ancestors and descendants. Stored in GEDCOM as a graph of INDI and FAM records.

Unlinked individual - A person in a GEDCOM file with no family connections. Usually a sign of a broken merge or an import error.

Vital records - Birth, marriage and death records (BMD).

Will - A legal document stating how someone's estate should be distributed on death. Frequently names children, spouse, siblings and grandchildren.

Y-DNA - DNA passed from father to son. Tracks the direct paternal line. Combined with surname patterns, often resolves disputed paternal lineage.