Noun
The number corresponding to a logarithm. The word has been sometimes, though rarely, used to denote the complement of a given logarithm; also the logarithmic cosine corresponding to a given logarithmic sine.
Source: Webster's dictionaryAs the function is the inverse function of log b (x), it has been called the antilogarithm. Source: Internet
The inverse function is the natural logarithm ln(x) ; because of this, some old texts citation refer to the exponential function as the antilogarithm. Source: Internet