arcane

American  

[ahr-keyn] / ɑrˈkeɪn /

adjective

1. known or understood by very few; mysterious; secret; obscure; esoteric.

   She knew a lot about Sanskrit grammar and other arcane matters.

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arcane British  

/ ɑːˈkeɪn /

adjective

1. requiring secret knowledge to be understood; mysterious; esoteric

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Other Word Forms

• arcanely adverb
• arcaneness noun

Etymology

Origin of arcane

First recorded in 1540–50; from Middle French, from Latin arcānus, from arc(ēre) “to enclose, restrain, ward off” (derivative of arca “box, chest, coffer”) + -ānus -an

Example Sentences

It may be an arcane discussion to most people, but the real-world implications of overhauling the Fed’s models are vast, and could shape monetary policy for years to come.

From Barron's • Feb. 18, 2026

I can’t tell you how many times I called or emailed the senior index analyst at S&P Dow Jones Indices to resolve some arcane question no one else could answer.

From The Wall Street Journal • Feb. 10, 2026

It’s been a crash course for him, he said, on the often arcane laws that govern who gets to stay in America and who doesn’t.

From Los Angeles Times • Feb. 1, 2026

Sometimes members of the audience would pass out while he tirelessly ranted about some arcane subject that mattered little, but he would draw applause nonetheless.

From Salon • Jan. 2, 2026

By now the reader will not be surprised to learn that an apparently arcane debate about the distant past could become vehemently personal.

From "1491" by Charles C. Mann

Related Words

• esoteric
• impenetrable