neck down
Advanced (C1)formal
To get narrower in the middle or at one end, like the neck of a bottle.
"The pipe necks down to 10mm at the joint to fit the smaller coupling."
Hear it in context

Office Episodes Only Kelly Could have Written
The Office · 9:49
She looks like Pam from the neck down.

Boz To The Future #27: The Future According to Shyam Sankar
Meta · 8:05
But if if we kind of neck down,

What "no brain" patients teach us about consciousness | Ideas For Our Time
The Institute of Art and Ideas · 15:25
true is the nervous system is also neck down, [laughter] right?

How to Confront Your Inner Critic (W/ Anu Gupta) | How to Be a Better Human | TED
TED · 31:00
You know, in their body, what I call neck down as well.

#UFCPerth Watch Along w/ UFC Hall of Famer Jens Pulver
UFC FIGHT PASS · 139:04
The kid got paralyzed from the neck down and now you're