Full Idea
For an object to be abstract, we require only that an understanding of any name of that object involves a recognition that the object is in the range of some functional expression.
Gist of Idea
Abstract objects must have names that fall within the range of some functional expression
Source
Michael Dummett (Frege Philosophy of Language (2nd ed) [1973], Ch.14)
Book Reference
Dummett,Michael: 'Frege Philosophy of Language' [Duckworth 1981], p.485
A Reaction
I'm not sure I understand this, but a function must involve a relation between some objects, such that a unique object is consequently picked out.