0 (zero; BrE: /ˈzɪərəʊ/, ZIRR-oh or AmE: /ˈziːroʊ/, ZEER-oh) is both a number and the numerical digit used to represent that number in numerals. It fulfils a central role in mathematics as the additive identity of the integers, real numbers, and many other algebraic structures. As a digit, 0 is used as a placeholder in place value systems. In the English language, 0 may be called zero, nought or (US) naught ( /ˈnɔːt/), nil, or — in contexts where at least one adjacent digit distinguishes it from the letter "O" — oh or o ( /ˈoʊ/). Informal or slang terms for zero include zilch and zip. Ought or aught ( /ˈɔːt/) has also been used historically. (See Names for the number 0 in English.)
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