Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
Similarly, a degree is high n if its n'th jump is the (n+1)'st jump of 0. Even more generally, a degree d is generalized high n if its n'th jump is the n'th jump of the join of d with 0′.
Soare, R. I. (1987). Recursively enumerable sets and degrees : a study of computable functions and computably generated sets. Berlin: Springer-Verlag. p. 71. ISBN3-540-15299-7.