Full Idea
Statements of the form '"it is snowing" is true if and only if it is snowing' and '"the world war will begin in 1963" is true if and only if the world war will being in 1963' can be regarded as partial definitions of the concept of truth.
Gist of Idea
'"It is snowing" is true if and only if it is snowing' is a partial definition of the concept of truth
Source
Alfred Tarski (The Establishment of Scientific Semantics [1936], p.404)
Book Reference
Tarski,Alfred: 'Logic, Semantics, Meta-mathematics' [Hackett 1956], p.404
A Reaction
The key word here is 'partial'. Truth is defined, presumably, when every such translation from the object language has been articulated, which is presumably impossible, given the infinity of concatenated phrases possible in a sentence.