As I was reading Old Mortality by Sir Walter Scott, I came across the following words, which sent me to the dictionaries and the encyclopedias.
Achan
A man mentioned in the Bible in the Book of Joshua in connection with the fall of Jericho and conquest of Ai. (Wikipedia)
Ci-devant
From or in an earlier time (used to indicate that someone or something once possessed a specified characteristic but no longer does so.) (Oxford Dictionaries, Wikipedia)
Erastianism
The doctrine that the state is superior to the church in ecclesiastical matters. It is named after the 16th-century Swiss physician and Zwinglian theologian Thomas Erastus, who never held such a doctrine. (Encyclopaedia Britannica)
Kailbrose
A traditional Scottish dish of creamed kale and oats (Celtnet Recipes; How Stuff Works, Visit Dunkeld) [I may have to try these kale brose recipes!]
Prelatist
A person who supported an episcopal view church government (Dictionary.com, Wikipedia, EHow)
Sybo
A spring onion (Dictionary.com)
Vidette
A mounted sentry in advance of the outposts of an army. (The Free Dictionary)