noun
esoteric writings; Upanishad
Refers to sacred Hindu treatises (Upanishads) or, more broadly, writings containing secret or profound teachings. The Upanishad sense is domain-specific.
インド哲学の奥義書を読むのは難しい。
Reading the Upanishads of Indian philosophy is difficult.
彼は奥義書を研究して、人生の意味を探求した。
He studied esoteric writings and sought the meaning of life.