\Man"nite\, n. [Cf. F. mannite.]
1. (Chem.) A white crystalline substance of a sweet taste
   obtained from a so-called manna, the dried sap of the
   flowering ash ({Fraxinus ornus}); -- called also
   {mannitol}, and {hydroxy hexane}. Cf. {Dulcite}.
2. (Bot.) A sweet white efflorescence from dried fronds of
   kelp, especially from those of the {Laminaria saccharina},
   or devil's apron.