the.com/bottleneck

means The narrowest point in a process — the slowest or most restricted step that limits how fast the whole system can go.

from A literal image before it was a business one: the neck of a bottle, physically narrower than the body, forces liquid to slow down and squeeze through. By the late 1800s and into the 1900s, engineers and economists had lifted the picture straight into traffic, factories, and workflows — any point where capacity pinches down, exactly like glass tapering toward the mouth of a bottle.