Build your vocabulary with Merriam-Webster's Word of the Day! Each day a Merriam-Webster editor offers insight into a fascinating new word -- explaining its meaning, current use, and little-known details about its origin.
February 27th, 2015
Episode 120 of 717 episodes
Merriam-Webster's Word of the Day for February 27, 2015 is: rationale \rash-uh-NAL\ noun 1 : an explanation of controlling principles of opinion, belief, practice, or phenomena 2 : an underlying reason : basis Examples: The newspaper's editorial reflected the concerns of many who questioned the rationale behind the mayor's decision. " the sacred trust that elected officials will share all options they've explored, identify the ones they haven't, and share the rationale behind their decisions." Robert F. Walsh, Stratford (Connecticut) Star, January 29, 2015 Did you know? The word rationale appeared in the second half of the 17th century, just in time for the Age of Reason. It is based on the Latin ratio, which means "reason," and rationalis, which means "endowed with reason." At first, rationale meant "an explanation of controlling principles" ("a rationale of religious practices," for example), but soon it began to refer to the underlying reason for something (as in "the rationale for her behavior"). The latter meaning is now the most common use of the term. The English word ratio can also mean "underlying reason" (in fact, it had this meaning before rationale did), but in current use, that word more often refers to the relationship (in number, quantity, or degree) between things.