Sindar is home to the humanoid species known as the Sindareen.
In 2359, Sindareen raiders attacked various parts of the main city on Betazed.
By 2368, the Sindareen have achieved several Pyrrhic victories over the Cordians, the Byfrexians, and the Luss, but have destroyed their own economy in the process. They invited ambassadors from these three races to a peace conference held aboard the USS Enterprise-D in orbit around Sindar. (TNG novel: Imzadi)