Sui generis
In sociology, the "sui generis" is what has been externalized, then internalized in the overall public and becomes a part of society that simply exists in its construct. It is not something that is not thought to have been created, because it is imbedded in everyone's way of thinking and being. Instances include the idea of love, or going to school, or clothing belonging to a specific gender. These examples are "sui generis" for they simply exist in society and are widely accepted without thoughts of where they come from or how they were created.
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.