Hollow back the normal cased book is a hollow back but this is assumed and therefore not specified. See back.

一般精装书籍均假定为空背，不用特别说明。参阅书背。

youdao

I sneaked out a quart jar of peaches, some cold corn bread, and a few Onions, and started up the hollow back of our house.

我偷了一罐桃子、几块冷玉米面包和一些洋葱，打算从后门走。

youdao

Back then they were made of naturally occurring objects - coconuts, sea shells, hollow stones or similar objects filled with moss or a similar material that was soaked with animal fat and ignited.

但是当时的它们是由天然材料制成的——椰子，贝壳，镂空的石头或相似的物体，里面装满苔藓，地衣或同样能吸收动物脂肪且容易点燃的材料。

youdao

Quail Hollow brings back good memories.

NPR: McIlroy Enters Next Phase Of Season

Still others have bent cucumber shaped pistons zooming back and forth in a huge, hollow cast-iron doughnut.

FORBES: Connect

The prisoner sank to his knees at the lip of the crater and looked back at the workers, his eyes hollow with terror, his mouth open and gulping air with rattling gasps through a parched throat.

NPR: Excerpt: 'Legends'