Full Idea
Necessary implication is often called 'strict implication'. The sort of strict implication found in valid arguments, where the conjunction of the premises necessarily implies the conclusion, is often called 'entailment'.
Gist of Idea
Necessary implication is called 'strict implication'; if successful, it is called 'entailment'
Source
Rod Girle (Modal Logics and Philosophy [2000], 1.2)
Book Reference
Girle,Rod: 'Modal Logics and Philosophy' [Acumen 2000], p.7
A Reaction
These are basic concept for all logic.