A scissors truss is a roof truss that creates a sloped ceiling instead of a horizontal ceiling. Unlike parallel-chord trusses — a type of truss that creates a sloped ceiling that is just as steep as the roof — a scissors truss creates a ceiling that has a gentler slope than the roof slope. You end up with a steep roof and a not-so-steep ceiling — in other words, a ceiling that is almost a cathedral ceiling but not quite.