Dolly Parton, a country singer, songwriter, entertainer, and entrepreneur whose success story, vibrant personality, remarkable vision, and talent set her apart, died Tuesday in Nashville. She was 80.

Her death was announced in a video posted on social media by her nephew, Brian Seaver. The cause of death has not been disclosed.

Concerns about Ms. Parton’s health, which began last year when she postponed and then canceled a series of performances in Las Vegas, reached such a point that last fall she confirmed on social media: “I’m not dead yet.”

In May, she said she had responded well to treatment after, in her words, her immune and digestive systems had “gone completely out of whack” in recent years.

Ms. Parton’s life, as chronicled in autobiographical songs such as “Coat of Many Colors” and “My Tennessee Mountain Home,” read like a work of fiction: from her humble beginnings in the Appalachians to her dazzling fame in Nashville and beyond.

Her songs have touched millions of people, addressing themes of hardship and loss while radiating possibility and hope.