"Shusseken" means something transcends "Seken," which refers to all the existence of the world corrupted by evils such as earthly desires.
The modern word 'Shusse' that is generally used to mean a successful career originated from 'Shusseken' and has five usages shown below. The usage 3 (and supposedly the usage 4) includes the state opposite to 'Shusseken', i.e., the state of being wrapped in 'Seken', which shows that the general usage diverges from the original religious meaning.
Various Buddha appear in the world to save all the living things.
To get away from the ordinary life to be converted to Buddhism
In the past, in Mt. Hiei of the Tendai sect, a son of a court noble ordained as a Buddhist priest by receiving the commandments of Buddhism and by shaving his head was called 'Shusseken.'
The modern general phrases like 'Shusse ga hayai' meaning 'rise by leaps and bounds' and 'Risshin shusse' meaning 'succeed in life' originated from the fact that the priests from court noble families were promoted fast.
In the Zen sect, to be the head priest of a temple. It means to transfer to a higher-ranked temple, to receive a yellow Buddhist garment or purple Buddhist garment, or to receive a rank of Osho (high priest).
To be born to this world.
In Buddhism, all the philosophical thoughts other than Buddhism, i.e., the non-Buddhist doctrines, are based on the secular wisdom that does not transcend attachments to things.
On the other hand, the Buddhist teachings advocate the transcendental wisdom that got rid of the attachments to things, which is called 'Shussekenchi.'