noun
writing profession; authorship
Refers to the occupation of writing, typically books or articles, as a profession.
彼は著述業で生計を立てている。
He makes a living as a writer.
執筆 is the act of writing, often used as a verb (執筆する), whereas 著述業 is the profession itself.
Compound of 著述 (writing, authorship) and 業 (profession, occupation).