What does that mean?

I just finished Gregory Maguire's Son of a Witch, the second novel in the wicked series. I actually left the book at Queen subway station a la bookcrossing...but without registering it. I hope someone picks it up an enjoys it!

While reading Son of a Witch, I came across MANY words that I was not familiar with. I don't usually look up the words I don't understand I just move along blissfully ignorant. This time I thought I would educate myself, although I probably should have looked up the words when I came upon them rather than waiting until I had finished (and given away) the book. OH WELL!

Here are the words I had to look up (using thefreedictionary.com):

1. concatenated: connected or linked in a series

2. propitiation: the act of placating and overcoming distrust and animosity, or the act of atoning for sin or wrongdoing

3. gelignite: a type of dynamite in which the nitroglycerin is absorbed in a base of wood pulp and sodium or potassium nitrate

4. perguenay: not in the dictionary, or anywhere online.....it was used in a sentence something like "the smell of perguenay smoke"

5. troika: a Russian carriage drawn by a team of three horses abreast

Questions: Were you familiar with these words? Do you ever look up the definition of a word you don't know?