The inner open space or cavity of a tubular organ, as of a blood vessel or an intestine.

腔管状器官的内部腔室或腔，窝，比如在血管或肠中的腔。

youdao

The round building is usually 3 to 4 stories tall with a large inner open space (single ring) or double rings.

那圆圆的建筑物一般是3至4层楼高，里面有一个大的空地（一圈）或者两圈。

youdao

The child had left the inner door wide open.

这个孩子让里面的门大开着。

《柯林斯英汉双解大词典》

Meanwhile, a cluster of small islands in the Inner Hebrides are being sold on the open market.

BBC: Community ownership mooted for Tanera Mor in Wester Ross

But at least the inner cores must, by treaty, remain open to new members.

ECONOMIST: A treat from Nice

Ruiz said he now plans to move from Las Vegas to his hometown of Boston in order to open a boxing gym in the inner city.

BBC: Ex-champion John Ruiz hangs up gloves