A cork fits into the neck of a bottle.

一个塞子塞在了瓶颈处。

youdao

Here I knocked off the neck of a bottle which I drew from a long row of its fellows that lay upon the mould.

说着我就从泥地上的一长溜酒瓶里，拿起一瓶酒，砸了瓶颈。

youdao

With a howl of rage, he grabbed the neck of a broken bottle and advanced.

他一声怒号，抓起一个破瓶子的瓶颈向前走去。

《柯林斯英汉双解大词典》

Aged in oak barrels for at least two years, Chianti Classico wines are identified by a black rooster within a red circle on the neck of the bottle, signaling membership of the Chianti Classico Consortium.

WSJ: Will Lyons on Wine: Consorting With Chianti