Full Idea
A propositional logic sentence is 'logically true', written |= φ, if it is true for every admissible truth-assignment.
Gist of Idea
'Logically true' (|= φ) is true for every truth-assignment
Source
José L. Zalabardo (Introduction to the Theory of Logic [2000], §2.4)
Book Reference
Zalabardo,José L.: 'Introduction to the Theory of Logic' [Westview 2000], p.53