The Collaborative International Dictionary of English v.0.48:

Donat \Don"at\, n. [From Donatus, a famous grammarian.]
   A grammar. [Obs.] [Written also donet.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Donet \Don"et\, n.
   Same as Donat. Piers Plowman.
   [1913 Webster]