1. In formal language theory and computer science, symbols in a grammar that can be replaced by other symbols or sequences of symbols; they are not part of the final output string.
Usage: technical; linguistics; computer science; plural form of nonterminal

Examples

• In the grammar rule S → NP VP, both S and NP are nonterminals.
• The parser uses nonterminals to represent abstract syntactic structures.
• Nonterminals are typically written in uppercase letters in formal grammars.
• The compiler distinguishes between nonterminals and terminals when building parse trees.
• Context-free grammars rely on nonterminals to define recursive language rules.