The set of all strings that can be derived from a grammar is said to be the language generated from that grammar. A language generated by a grammar G is a subset formally defined by L (G)= {W|W ∈ ∑*, S ⇒G W} If L (G1) = L (G2), the Grammar G1 is equivalent to the Grammar G2.

Language generated by a grammar – Given a grammar G, its corresponding language L (G) represents the set of all strings generated from G. Consider the following grammar, G: S-> aSb|ε In this grammar, using S-> ε, we can generate ε. Therefore, ε is part of L (G). Similarly, using S=>aSb=>ab, ab is generated.

The language generated by a grammar is the set of all strings of terminal symbols that can be derived, by repeated rule applications, from some particular nonterminal symbol ("start symbol"). Nonterminal symbols are used during the derivation process, but do not appear in its final result string.

A generative grammar is a formal system which is built from a finite number of ingredients, but provides an explicit way of constructing (generating) a potentially infinite set of strings of atomic symbols and possibly associates each of these strings with a constituent structure.

The language L generated by grammar G = (N, Σ, P, S), is defined by L = L(G) = { x | S *=> x and x is in Σ* }