Terminal Symbol

A Terminal Symbol is an abstract symbol from a terminal symbol set that can be used to generate a formal sentence.

• AKA: Formal Syntax/Grammar/Language Terminal Symbol.
• Context:
  • It can be a Natural Language Terminal Word from a Natural Language Lexicon.
• Example(s):
  • a Lexical Item.
  • a Programming Token.
  • a Mathematical Token.
  • …
• Counter-Example(s):
  • a Non-Terminal Symbol.
• See: Constant, Disjoint Sets, Formal Grammar, Formal Language.

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References

2016

• (Wikipedia, 2016) ⇒ https://en.wikipedia.org/wiki/Terminal_and_nonterminal_symbols Retrieved:2016-5-23.
  • In computer science, terminal and nonterminal symbols are the lexical elements used in specifying the production rules constituting a formal grammar. Terminal symbols are the elementary symbols of the language defined by a formal grammar. Nonterminal symbols (or syntactic variables) are replaced by groups of terminal symbols according to the production rules.

    The terminals and nonterminals of a particular grammar are two disjoint sets.

2009

• http://www.cse.unsw.edu.au/~billw/nlpdict.html#terminal
  • A terminal symbol of a grammar is a symbol that can appear in a sentence of the grammar. In effect, a terminal symbol is a word of the language described by the grammar.

    See also non-terminal symbol and context-free grammar.

2007

• (Kakkonen, 2007) ⇒ Tuomo Kakkonen. (2007). “Framework and Resources for Natural Language Evaluation." Academic Dissertation. University of Joensuu.
  • Definition 3-1. Symbol, terminal and alphabet.
    • A symbol is a distinguishable character, such as “a”, “b” or “c”.
    • Any permissible sequence of symbols is called a terminal (also referred to as a word).
    • A finite, nonempty set ∑ of terminals is called an alphabet.
  • Definition 3-2. String and sets of strings.
    • Let Σ be an alphabet.
    • A finite sequence of symbols S=(x1 x2… xn), n≥0, x∈Σ is called a string in alphabet Σ.

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