1. （艺术作品的）陈列室，展览馆；画廊
    A gallery is a place that has permanent exhibitions of works of art in it.

    e.g. ...an art gallery.
           美术馆
    e.g. ...the National Gallery.
           国家美术馆

2. 私人画店；私人画廊（或画室）
    A gallery is a privately owned building or room where people can look at and buy works of art.

    e.g. The painting is in the gallery upstairs.
           那幅画在楼上的画廊里。

3. （大厅的）楼座，边座，楼上旁听席
    A gallery is an area high above the ground at the back or at the sides of a large room or hall.

    e.g. A crowd already filled the gallery.
           楼座已经挤满了人。

4. （剧场或音乐厅中通常票价最低的）顶层楼座
    The gallery in a theatre or concert hall is an area high above the ground that usually contains the cheapest seats.

gallery

    e.g. They had been forced to find cheap tickets in the gallery.
           他们不得已买了顶层楼座的廉价票。