Full Idea
The types is 'ramified' because there are further differences between the type of a function defined in terms of a quantifier ranging over other functions and the type of those other functions, despite the functions applying to the same simple type.
Gist of Idea
Types are 'ramified' when there are further differences between the type of quantifier and its range
Source
Bernard Linsky (Russell's Metaphysical Logic [1999], 1)
Book Reference
Linsky,Bernard: 'Russell's Metaphysical Logic' [CSLI 1999], p.4
A Reaction
Not sure I understand this, but it evidently created difficulties for dealing with actual mathematics, and Ramsey showed how you could manage without the ramifications.