Full Idea
Normally, to say that a sentence Φ is 'satisfiable' is to say that there exists a model of Φ.
Gist of Idea
A sentence is 'satisfiable' if it has a model
Source
Stewart Shapiro (Philosophy of Mathematics [1997], 4.8)
Book Reference
Shapiro,Stewart: 'Philosophy of Mathematics:structure and ontology' [OUP 1997], p.135
A Reaction
Nothing is said about whether the model is impressive, or founded on good axioms. Tarski builds his account of truth from this initial notion of satisfaction.