Full Idea
We say that an argument a 'satisfies' a function φx if φa is true.
Gist of Idea
An argument 'satisfies' a function φx if φa is true
Source
Bertrand Russell (Introduction to Mathematical Philosophy [1919], XV)
Book Reference
Russell,Bertrand: 'Introduction to Mathematical Philosophy' [George Allen and Unwin 1975], p.164
A Reaction
We end up with Tarski defining truth in terms of satisfaction, so we shouldn't get too excited about what he achieved (any more than he got excited).