Definition of rationate in English:

rationate

Pronunciation /ˈraʃ(ə)neɪt/

verb

rare
  • To reason; to ratiocinate. Occasionally with object.

Origin

Mid 17th century; earliest use found in Kenelm Digby (1603–1665), natural philosopher and courtier. From post-classical Latin rationat-, past participial stem of rationari to reason from classical Latin ratiōn-, ratiō.