The Latin roots of orotund are related to two more common English words-oral and rotund. Latin or- means "mouth," and rotundus means "round" or "circular." The Roman poet Horace joined forms of those Latin terms to create the phrase ore rotundo, literally meaning "with round mouth," and figuratively meaning "with well-turned speech." Ore rotundo was modified to orotund and adopted into English in the late 18th century. It can indicate either strength of delivery or inflated wording.
(Via Merriam-Webster's Word of the Day)
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