The Collaborative International Dictionary of English v.0.48:

Ascii \As"ci*i\, Ascians \As"cians\, n. pl. [L. ascii, pl. of
   ascius, Gr. ? without shadow; 'a priv. + ? shadow.]
   Persons who, at certain times of the year, have no shadow at
   noon; -- applied to the inhabitants of the torrid zone, who
   have, twice a year, a vertical sun.
   [1913 Webster]