Ascendancy
Ascendancy is a concept not unlike the American Dream, it's a dream that anyone can become anything they want and it is held by many in the Realms.
Usage
Much like in our world, this is an empty dream filled with powerful people wanting to enthrall the individuals while still encouraging the dream to instill a sense of meaning in fairly meaningless lives. Like gambling or drinking, it is a carrot for people to hang on to a dream in a depressing, short, life while doing their best - which mainly helps others than themselves.
However, there is much more presedence for this type of hopes in the Realms than in our world because the whole powerbase is resting on the shoulders of individuals "who made it", who experienced Ascendacy. The power of the Family Register is almost entirely hinged on the fact that the gentry is changing and the Register can be a supporting force for those who gained power to retain it and new "houses" are frequently created in battles around the Realms by being raised to Firstknight. There are also those who attempt the action Kingdom by Might (and though these fail, as a rule, their myths live on).
Most of these annointed Firstknights (also known as Tyrospur, hedge knight or wandering knight) never achive proper "ascendancy" in the form of an heredetary title such as a Peer Knight and beyond, but their mere existence (and very visible/annoying existence in peace times) of them keep fuelling the wheels of production for Regents in the Realms and of the hundreds of armed conflicts of various size that happens on any given year.