rationale

The word 'rationale' entered English in the 17th century from the Latin rationalis, meaning 'of or belonging to reason'. This Latin term was derived from ratio, which originally signified a 'reckoning' or 'calculation' but evolved to mean 'reason' or 'judgment'. The modern English noun 'rationale' preserves this core sense of reasoned calculation, specifically denoting the logical foundation that explains or justifies a decision. Its journey reflects a specialization from the general concept of reasoning to the specific presentation of the reasoning behind an action.

Structure: ration (reason) + ale (noun suffix) - ration: From Latin ratio (reckoning, reason, calculation). Functions as the core root conveying the sense of 'reason'. - ale: A variant of the noun suffix -al, from Latin -alis, used to form nouns meaning 'an act or process'. In this word, it is part of a fused suffix -ale.