[ar.ca.num] n, pl -na [L, fr. neut. of arcanus secret, fr. arca chest--more at ark] (15c) 1: mysterious knowledge, language, or information accessible only by the initiate--usu. used in pl.
2: elixir 1
[ar.ca.num] n, pl -na [L, fr. neut. of arcanus secret, fr. arca chest--more at ark] (15c) 1: mysterious knowledge, language, or information accessible only by the initiate--usu. used in pl.
2: elixir 1
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012