WHAT IS IT?
Our word for today is the most obscure one that I could find and it is notable for being the only word that will earn you a million billion points if you manage to play it in Scrabble.
Porphyrogeniture is the principle of royal succession in which the first son born after his fathers accension to the throne has the first claim to it.
Even if he has older brothers who were born before the fathers crowning 
WHERE DO YOU GET IT?
USING IT IN REAL LIFE:
This is a highly specialised thing and aside from using it with a royal or two 
You might institute it if you had taken over a small but profitable banana republic in a well planned military coup against the king and and declared yourself "El Grande Presidente Fabulouso for life.
The catch was that you did all this with the assistance of the kings dastardly son who suddenly turns up demanding to be put on the throne. Suddenly declaring that Porphyrogeniture is in effect will most likely work as a delaying tactic while everyone runs to the library to look it up.
USING IT IN WRITING:
The most obvious use for it is going to be the scenario mentioned above. The elder son is not qualified to be king due to the fact that his father hadn't been crowned when he was born. But his little brother, naturally, is. It doesn't take a rocket scientist to figure out that someone is going to be scheming at the Olympic level.
To move away from "The wicked prince" scenario it might be that the elder prince really doesn't want the throne  However there are certain factions about the place who do want him in the big boys chair for reasons that remain their own  Suddenly the prince is in the middle of several murder investigations and there are similar attempts on his younger brothers life.
What happens if some peasant, through a very convoluted series of coincidences manages to give birth in the right room at the proper time. 20 years later the peasant king steps out to group his subjects. 
MIGHT ONE TAKE OVER THE WORLD WITH IT?
is also for
PRATT, T.A 
Author of the Marla Manson series which can best be described as magic exists. People that use magic are sometimes not very nice. Marla Manson is straightforward enough to cut through all the crap and start kicking the butt  of the people who started up the trouble in the first place.
On the whole I like the writing with my only little niggle being that Marla, the main character, has a wee touch of Mary Sue about her. The books themselves are fairly short. a couple of hours being more than enough to finish the first and move onto the second 
I would recommend this series to any who like modern day magicians dealing with ancient and terrible problems.
- Sounds like a reasonable scheme. Surely nothing can go wrong with this.
- The author assumes that those who read this have access to a functioning TARDIS or similar machine and are also fully conversant with the laws of probability/causality and that one about not wearing a duck while crossing over from Canada to America.
- Probably two. It pays to be respectful of the people in the big shiny chairs who command the people with the nasty pointy swords
- It's crazy I know but bear with me on this one
- what are you looking down here for? I certainly don't know what the plans are!
- Presumably with a soundtrack by Phil Collins.
- I realize that P is also for Pratchett, Terry but I didn't want to go for the obvious choice. That being said, OMG DISCWORLD I LOVE YOU! I think that sums up my feelings on the matter fairly well.
- or asses. Singular or collective doesn't really matter Butts will be kicked liberally.