a. (or c.) about (or circa, in Latin), normally used in front of uncertain dates
AG Accredited Genealogist -- a designation conferred by the Church of Jesus Christ of Latter-day
Saints (LDS).
Adjutant General's Report: a published account of the actions of military units from a particular state during a war.
Adoption: to be declared part of a family from which you were not born -- although we think of legal adoptions in this centuries, you may run into cases that are otherwise in your research, meaning the individual may have taken the family name because they were raised there; but no legal proceedings were ever instituted or finalized.
Ahnentafel -- a German genealogical numbering system. The word means "ancestor table" and the format is more than 100 years old. Ahnentafel is a way of numbering that has a mathematical relationship between parents and children. Can also be referred to as he Sosa-Stradonitz System of numbering. The ahnentafel lists all known ancestors of a person and includes the full name, dates and places of birth, marriage, and death. All males in the table are even numbers and all females are odd numbers.
Albumen Print: A type of photograph typically taken between 1858 and 1910 that was produced on a thin piece of paper coated with albumen and silver nitrate, often mounted on cardboard.
Ambrotype: Kind of photograph printed between 1858 and 1866 on thin glass. Photo often has a black backing.
Ascention --
Abstract -- the summary of critical information in a document or website; commonly used in reference to deeds or wills.
Ancestral File -- A searchable collection of fenealogical information submitted to the LDS archives which house more than 40 million names. Files are in GEDCOM format to help genealogy buffs cordinate their research with various groups, organizations, and computer programs. This information is accessible to everyone, regardless of religious choice.
Ancestors -- those individuals from whom you descent, such as parents, grandparents, and further up your family tree.
BCG -- Board for Certification of Genealogists.
Bulletin Board -- On-line message system where individuals can post comments, queries, and information about ancestors or their research. There are thousands available on the net. Can also be called a forum or message board.
Cadastre -- a survey, map, or other public record that shows ownership and value of property/land for tax purposes.
Cenus -- A counting of the human population, usually instituted by a governmental agency. Depending upon the year and type, it may give only brief numerical information, or more detailed lists including household members, occupation, educational background and more.