What is Validity and Satisfiability in a propositional statement?

A formula is valid if it is true for all values of its terms. Satisfiability refers to the existence of a combination of values to make the expression true. So in short, a proposition is satisfiable if there is at least one true result in its truth table, valid if all values it returns in the truth table are true.


Satisfiability -the other way of interpretation
A propositional statement is satisfiable if and only if, its truth table is not contradiction.
Not contradiction means, it could be a tautology also.

Hence, every tautology is also Satisfiable.
However, Satisfiability doesn't imply Tautology.

Another thing to note is, if a propositional statement is Tautology, then its always valid.

Thus, Tautology implies ( Satisfiability + Validity ).


From Wikipedia,

A well formued formula (wff) is satisfiable if it can be made TRUE by assigning apt logical values to its variables.

On the other hand, a wff is valid only if it's true under every interpretation. In propositional logic, wff's are valid only if they are tautologies.

The wff that you have stated in your question is satisfiable but not valid because its not a tautology which you can easily prove using Truth Tables.