0 (zeroBrE/ˈzɪərəʊ/ or AmE/ˈziːroʊ/) is both a number[1] and the numerical digitused to represent that number in numerals. It fulfils a central role in mathematics as theadditive identity of the integersreal 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 zeronought or (US) naught /ˈnɔːt/nil, or — in contexts where at least one adjacent digit distinguishes it from the letter "O" — oh or o /ˈ/. Informal or slang terms for zero include zilch and zip.[2] Ought or aught /ˈɔːt/ has also been used historically.[3](See Names for the number 0 in English.)