What has a neck but no head?

Why this works

This riddle plays on the double meaning of the word "neck." In one sense, a neck refers to the part of a bottle that is narrower than the body, allowing for easy pouring. In contrast, the term "head" usually signifies the top part of something that contains a brain or face. Since a bottle has a neck but lacks a head in the traditional sense, the answer cleverly highlights this playful use of language!