What’s the difference between paramount and tantamount? The distinction is of paramount importance; it’s tantamount to being right or wrong.
Paramount, from the Anglo-French word paramont, derived from the Latin phrase per ad montem, literally translated as “up the mountain,” means “supreme.” It’s also used (rarely) as a noun to refer to a supreme ruler. Tantamount was originally a noun, translated into English from the Anglo-French phrase tant amunter, meaning “to amount to as much,” and means “equivalent.” It is seldom used — more’s the pity, because it is such a grand word — in such phrases as “tantamount to treason.”
This grandiloquence, and the word’s resemblance to paramount, may mislead writers into assuming it has a lofty sense like its counterpart.
As you might have guessed, the noun amount, meaning “sum,” also derives from the Latin word for mountain. Another word with the element -amount is catamount, a nearly obsolete synonym for cougar or lynx that is a compression of the term cat-a-mountain.
Closed-compound verbs with the root word mount include dismount (“remove oneself from a high position, as a horse or a piece of gymnastic equipment,” or “take apart”) — demount is a rarely used variant — remount (“get up on again,” or “revert”), and surmount (“climb,” “excel,” or “overcome,” or “be at the top of”).
Seamount is a noun referring to an underwater mountain whose summit does not reach sea level. (If it did, it would be called an island.) Dismount and remount also have noun forms; the former refers to the concluding movement in a gymnastics routine, and the latter denotes a horse that replaces a rider’s previous one.
An interesting side note: In archery, “lord paramount” and “lady paramount” are terms for an official in charge of an archery tournament, or for a ceremonial leader of such an event, equivalent to a parade grand marshal. The terms originated in the feudal era, when a lord paramount, one not subordinate to a member of the nobility of greater rank, was required to provide trained longbowmen in the event of war, and officiated at archery tournaments. (The title “lord paramount” is known to fans of the television series A Game of Thrones and the series of novels on which it is based.)