/trʌs/
[noun] A framework of beams or bars, usually arranged in triangles, used to support a roof, bridge, or other large structure. It can also refer to a bundle of hay or straw tied together, or a medical device worn to support a hernia.
A truss began life as a bundle of hay — centuries before engineers borrowed the word to hold up bridges and cathedrals.
The word 'truss' arrives in English during the 13th century, carried across the Channel by the Norman French after the Conquest. Its immediate source is the Old French word 'trousse', meaning a bundle or package — the kind of tightly bound collection of things you might tie together for transport. This Old French form descended from the verb 'trousser', meaning to tie up or bundle, which is where the real journey begins.
Tracing 'trousser' further back takes us into murkier but fascinating territory. Most scholars connect it to a Vulgar Latin form, 'torsare' or 'torsiare', derived from the classical Latin 'torsus', meaning twisted or wrung — itself related to 'torquere', to twist. From that same root Latin 'torquere' → Old French 'torque' → English 'torque' (a twisting force), and also Latin 'torquere' → Latin 'tortus' → Old French 'tort' → English 'tort' (a legal wrong, implying something bent out of shape). The essential idea is one of tightness, tension, and things wound or coiled together.
In its earliest English uses, a truss was simply a bundle — most commonly a measured bundle of hay or straw. Merchants and farmers knew exactly how much a 'truss of hay' weighed, because it was a regulated unit of trade. This practical, agricultural sense kept the word grounded in everyday commerce for centuries, long before it acquired any architectural meaning.
The engineering sense of 'truss' — a rigid framework of triangulated supports — emerged gradually as builders and architects needed a word for the interlocking beam structures they were using to span wide spaces. By the 16th and 17th centuries, carpenters building roof frames were using the word to describe the angled timber assemblies that distributed weight so efficiently. The logic connecting the two senses is elegant: both a bundle of hay and a structural truss involve things bound tightly together so they act as a single, stronger unit.
A third meaning developed along a quite different path — the medical truss, a supportive device strapped around the body to hold a hernia in place. This sense, recorded from the 16th century onward, draws directly on the original idea of binding or holding something firmly together. To 'truss up' a patient, or indeed a chicken before roasting, kept that old French sense of tying and bundling vividly alive in everyday speech. The culinary use — trussing a bird — remains widely understood today and is perhaps the most direct living link to that original Norman bundle of hay.