[ ˌratɪɒsɪ'neɪʃ(ə)n , ˌraʃɪ- ]
■ noun formal the forming of judgements by a process of logic; reasoning.
Derivatives
ratiocinate verb
ratiocinative adjective
ratiocinator noun
Origin
C16: from L. ratiocinatio(n-) , from ratiocinari 'deliberate, calculate', from ratio (see ratio ).