Delavi was a binary star in the Alpha Quadrant, located near the border of the United Federation of Planets and the Cardassian Union. (ST reference: Star Charts)
A moon on the third planet of the Delavi system was the site of a covert Cardassian base during the Federation-Cardassian War, which was seized by the USS Gettysburg in 2328. (SCE eBook: Turn the Page; ST - Terok Nor novel: Day of the Vipers)
The USS Gorkon spent three weeks defending the Delavi system during the Dominion War. (ST novel: Articles of the Federation)
This system was the origin of Delavian chocolate. (DS9 episode: "Improbable Cause")