Definitions

1. adjective

secret or mysterious, especially in an obscure or technical way

“The arcane symbols on the ancient scroll were difficult to decipher.”

2. noun

a mysterious or obscure subject or practice

“Alchemy was once considered an arcane art, but it has since been largely discredited.”

3. noun

a mysterious or obscure term or expression

“The professor used an arcane phrase to describe the complex concept.”