a. (Chem.) Of, pertaining to, or designating, a hypothetical sulphacid (called also thioarsenious acid) analogous to arsenious acid, and known only in its salts. [ 1913 Webster ]
[あひさん(亜砒酸);あヒさん(亜ヒ酸), ahisan ( a hi san ); a hi san ( a hi san )](n) (1) arsenious acid; arsenous acid (H3AsO3); (2) (col) arsenic trioxide; white arsenic (As2O3)[Add to Longdo]