ACW: Nickname for American Civil War.
Authentic: A item or portrayal that was in use at the time of the Civil War. Can be backed up by documentation.
Black Powder Enthusiasts: Generally refers to the folks who do Mountain Man Rendezvous and black powder shooting contests. Unlike Civil War reenactors they actually shoot stuff out of their muskets.
CAS: Cowboy Action Shoot. Competition shooting done with live rounds.
Character: The Civil War era person you portray at reenactments. This can be either an actual historical figure, an ancestor, or a fictional persona created out of your personal research.
Character Biography: Really good reenactors take the time to develop a biography for the character they play. You should know when & where your character was born in relation to the era you portray, what type of historic events they witnessed, family life, personal traumas, economic & social background, etc. The more background you build into your character, the better your portrayal.
Composite Interpretation: Also called Representative Interpretation. Portraying a fictional character who did not actually live during the Civil War, but is a character based on your historical research. An example would be researching Civil War nurses like Aunt Lizzie Aikens and Mary Ann Bickerdyke, then developing a nurse character based on your studies.
De-FARB: To remove or conceal any modern items in an encampment. This is an order called out about 1/2 hour before camps open to the public.
Documentary Interpretation: Portraying a known historical character from the times. This is usually done by someone who resembles the character and has done extensive research on that person.
FARB: Used as both an adjective and a noun. Indicates a reenactor, item, or activity that is not an accurate portrayal of the times - an anachronism or modern item. Supposed to be short for "Far be it for me to tell you that was not around during the Civil War." Examples are a costumed reenactor wearing modern glasses or sitting in an aluminum lawn chair, or ladies wearing prom gowns, or a costume created from polyester fabric. Term is usually applied to very obviously inaccurate portrayals or items.
First Person Interpretation: Assuming the speech, attitudes and actions of the Civil War character you are portraying. You must also seem to have no knowledge of anything from modern times.
Motel Militia: Reenactors who retire to a motel after the days activities rather than camping out. Also used to refer to the non-reenacting spouses and family members of reenactors who do not participate but come along to the events as spectators. Also called Ramada Rangers.
Necessary (The): The little blue porta-potties/outhouses/chemical toilets found at reenactments. "The necessary" was actually a period term for outhouse. Also called Comfort Station, Hooters, Irish Shanty, Officer's Quarters, and Our Lady of the Blue Waters.
Out of Character: To cease your first person interpretation, usually long enough to answer a question posed by a visitor, such as a request for membership information. Removing the hat is the usual indicator that a reenactor is no longer in character.
Period Correct: An item or portrayal that would have been right at home during the Civil War era.
SCA: The Society for Creative Anachronism. Medieval and renaissance hobbyists who may sometimes be found at renaissance fairs.
Thread Nazi: Also called Thread Counters, Authenticity Nazi's, or Fashion Police. An individual who feels that their life calling is to point out the perceived inaccuracies in other's costumes. Although any well meaning reenactor will tactfully and helpfully inform you of mistakes you might be making while you are starting out, this term is often applied to folks who go a tad overboard or are rude/nasty when making their terse comments on your garb.
Tin Tepee: An RV, camper, or travel trailer. Borrowed from Rendezvous folks.
Work: Also Job, Career, Employment, 9 to 5. That which we must endure to support our hobby.
Your Time/My Time: Used to refer to a type of reenacting where the character has been "time transported" into the modern day. The reenactor portrays a historic character who has knowledge of modern times, as in "Well, in my day we didn't have electric lights..." Often a useful ploy when doing presentations to children's groups, or conversing with visitors who have trouble playing along with a first person character.
Yuppie Larva: Used to refer to peevish children at events, specifically those who already know everything about history cuz' they saw it on TV.
Sources for More Information
These websites offer great information on the period terms and slang that would be used by civilian reenactors.