arcanum
Could not find arcanisque in Logeion dictionaries.
arcanisque Noun: neuter ablative plural, Noun: neuter dative plural of arcanum
1 arcānum, (11) ī, n. (arcanus), secret : Hor. O. 1, 18, 16 ; Ov. M. 7, 192, etc.
Baillifin Diction. Spagyrico :