*kaput-

The core idea of this root was:

head

The root is a subbranch of the root *kap-, which was about grasping, containing. The idea of “head” comes from the “head” essentially being a bowl, a container for the brain.

The notion of head is still visible in most of the offspring in today’s English.
Here’s a little (incomplete) overview:

• head
• Capo (Latin for “head”)
• captain (“head”)
• chef, chief, chieftain (“head”)
• capital (“head city”)
• cattle (“what you own, are the boss of”)
• capital (“what you own, what you’re the captain of”)
• decapitate (“remove head”)
• cabbage (looks like a head)
• chapter (originally “little headline, section”
• capitulate (originally “drawing up piece terms”, based on the idea of chapter)
• recapitulate (“go over the chapters”)
• biceps, triceps (“two-head, three-head”)