Sui generis
In local government, a "sui generis" entity is one that does not fit with the general scheme of local governance of a country. For example in England, the City of London and the Isles of Scilly are the two "sui generis" localities, as their forms of local government are both (for historical or geographical reasons) very different from those of elsewhere in the country. 
In a press conference during which reporters were trying to analyse his political personality, Huey Long said, "...say that I am "sui generus", and let it go at that."
Order of succession
Proximity of blood is a system wherein the person closest in degree of kinship to the sovereign succeeds, preferring males over females and elder over younger siblings. This is sometimes used as a gloss for "pragmatic" successions in Europe; it had somewhat more standing during the Middle Ages everywhere in Europe. In Outremer it was often used to choose regents, and it figured in some of the succession disputes over the Kingdom of Jerusalem. It was also recognized in that kingdom for the succession of fiefs, under special circumstances: if a fief was lost to the Saracens and subsequently re-conquered, it was to be assigned to the heir in proximity of blood of the last fief-holder.