Ridgepole

Part of speech: noun

Pronunciation: /ˈɹɪdʒpəʊl/

Definitions

1. A horizontal beam that provides crucial support at the highest point of a roof, linking the upper sections of the sloped structures and ensuring they remain stable
2. A beam positioned horizontally along the top of a roof structure to maintain stability and connect sloping sides
3. A structural element running across the highest part of a roof that holds the upper portions together securely

Etymology: A ridgepole is about as literal as compounds get: a beam running along the highest line of a roof, where the rafters meet. The "ridge" half is the old word for the topmost crest of anything, from a hill to a backbone, and the "pole" half is a long, straight timber, so the name simply describes the piece of wood sitting along the top. Builders have been using a single long central beam this way for centuries, and the word tells you exactly where it goes. The compound is transparent in both parts, which is why its meaning has barely shifted since it was formed. Where the word does stretch is in the other direction: "pole" in this sense does not mean a pole in the sense of a stick stuck in the ground, but a long, dressed piece of timber, so the pairing is really "crest-timber" rather than anything about height or vertical posts.