Most genealogies typically following Chicago Manual of Style, 15th edition. Here are some common styles used in genealogy.

Style

• Spell out numbers one through one hundred. There are exceptions to this, however, so consult Chicago Manual of Style.
• Spell out centuries, e.g., nineteenth century, not 19th century.
• No apostrophes in plurals of years, e.g., 1890s, not 1890’s
• Dates should be written as day, month, and full year, e.g. 17 October 1999.
• If only a month and day, then October 17, not 17 October.
• Use serial commas, e.g., red, white, and blue; not red, white and blue.
• Initials after names should have no periods, e.g., Nancy Thistlebottom, CG.
• Use small caps for initials, not all caps, e.g. CG, not CG
• Use small caps for A.M. and P.M.
• No comma between a surname and senior or junior, e.g., Robert Evans Jr.
• Avoid sexist language. Either change the sentence to a plural, or use he or she, him or her. Or alternate use of he and she in examples. Do not use he/she, him/her, or s/he. Replace “manmade” with “artificial” or “synthetic,” replace “mankind” with “humanity,” replace “layman” with “lay person,” etc. A possible exception is if the author is using a gender specific pronoun when referencing historical situations where only men or women participated. “If your ancestor served in the Revolutionary War, then he…”
• Web site addresses should be written as within text or citations. If listed in a resource list, do not use the <>.

Words (commonly used or misused)

• African-American. Use hyphen when used as a compound modifier, e.g. African-American genealogy. No hyphen when used as noun, e.g., She is African American.
• Ahnentafel
• ancestor, not direct ancestor (all of your ancestors are “direct” ancestors)
• appendixes, not appendices
• base line (two words)
• backward/forward, not backwards/forwards
• birth date (two words)
• birthplace (one word)
• Brøderbund
• bylaws, not by-laws
• CD-ROM, not CD-Rom
• census, censuses
• Church of Jesus Christ of Latter-day Saints (day is not capitalized)
• courthouse, not court house
• database (one word)
• descendant, not direct descendant
• enumeration district (In text, spell out and lower case. In a record citation, use E.D.)
• e-mail (lower case)
• family Bible (cap Bible)
• Family History Library, Family History Centers (cap)
• FamilySearch (one word)
• fax (lower case)
• great-grandfather/mother (use hyphen) or great-great-grandfather/mother
• indexes, not indices
• Internet (cap)
• internment vs. interment. Interment is the act of being interned, such as in a prisoner of war camp; interment is the act of burial.
• immigrate vs. emigrate/immigrant vs. emigrant. Immigrate/immigrate is used when the person enters the country;
• migrate/emigrant is used when the person is leaving the country; e.g., He emigrated from Italy. He immigrated to America.
• keynote speaker, not key-note or key note
• lectern, podium: a speaker stands behind a lectern and on a podium
• mother-in-law, father-in-law; plural mothers-in-law, fathers-in-law
• National Society, Daughters of the American Revolution (not National Society of the Daughters of the American Revolution)
• National Union Catalog of Manuscript Collections (ital)
• NUCMC (Roman, all caps)
• New Style calendar (no hyphen, and cap)
• Old Style calendar (no hyphen, and cap)
• online, not on-line
• Periodical Source Index (italicize when written out)
• PERSI (Roman, all caps)
• quitclaim (one word); but quit rent (two words)
• Reverend: precede with “the” when Reverend is spelled out and used before a person’s name; do not precede with “the” when using the abbreviation Rev., e.g. the Reverend Jacob Shough, Rev. Shough
• self-addressed, stamped envelope or an SASE
• state names: use two-letter postal abbreviations in addresses; spell out names of states in text.
• stepbrother/father/mother/sister (one word, no hyphen)
• syllabus, syllabuses
• teenage or teenager; one word, no hyphen
• toward, not towards
• United States; spell out when used as a noun; U.S. (no spaces) when used as an adjective
• vice president (no hyphen)
• videotape (one word)
• Web site (cap Web)