Full Idea
To say that the name x denotes a given object a is the same as to stipulate that the object a ... satisfies a sentential function of a particular type.
Gist of Idea
A name denotes an object if the object satisfies a particular sentential function
Source
Alfred Tarski (The Concept of Truth for Formalized Languages [1933], p.194)
Book Reference
'The Nature of Truth', ed/tr. Lynch, Michael P. [MIT 2001], p.382