grand residence, especially a royal residence or the home of a head of state

A palace is a place with a grand and imposing building that is the official residence of a king or queen, a head of state such as a president, or a high-ranking aristocrat or church dignitary.

A palace in India, built in a lake

Besides, it can mean a large building for entertainment: a large public or private building with an imposing ornate style, used for entertainment or exhibitions and large events.