Treenails

Part of speech: noun

Definitions

1. Long wooden pins driven through holes to fasten the planks and timbers of a wooden ship or frame
2. Hardwood dowels hammered into bored holes to join structural timbers, especially in old wooden vessels
3. Cylindrical oak pegs that secure boat planking to its framework by being driven through aligned bores

Etymology: "Treenails" is the plural of "treenail", a wooden peg used to fasten timbers together, most famously in old wooden ships and buildings. The "tree" in the word is not the living plant but an old spelling-and-sound survival of "tree" in the sense of wood, so a treenail is literally a "wooden nail." Shipbuilders drove these long oak pegs through the planks and into the frame, where they swelled slightly once wet and held the joint tight without iron rusting or corroding. The word came into English from Middle English "trenayl", which was itself a compound of "tree" and "nail." Over the centuries the spelling drifted, and "trenail" and "treenail" were both used, with the latter pronounced in a way that preserved the older "tree" form. The word is a plain, transparent compound: the surprise lies less in its parts than in how literally it describes a fastening made of wood.

Synonyms: trenail, trunnel, dowel