From Old French trousse 'bundle,' from Latin torquēre 'to twist,' for beams bound together into a rigid structural framework.
A rigid framework of beams forming triangles, used to support roofs, bridges, and other structures.
From Old French trousse 'bundle, package,' from trousser 'to bind together, tuck up,' possibly from Vulgar Latin *torsāre, from Latin torquēre 'to twist.' The structural engineering sense developed because a truss binds beams together into a rigid unit. The triangular configuration was mathematically proven optimal by the 19th century. Key roots: *terkʷ- (Proto-Indo-European: "to twist").
A trousseau (a bride's collection of clothing) shares the same root as a truss—both are things 'bound together into a bundle.' A bride's trousseau was literally her trunk of bundled belongings.