What does antilogarithm mean?
The definition of antilogarithm
An`ti*log”a*rithm, n. (Math.)
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.

— An`ti*log`a*rith”mic, a.