I always understood trouser jeans to be styled like dressy slacks, with features like slanted pockets, front or back welt pockets, no double seams or top stitching, regular fly zipper, or using back or side zippers, more tailored waistband or faced waistline, invisibly hemmed. But the fabrication is jeans - denim, or even chambray.

Now I see trouser jeans that to me are just jeans, with rivets and metal buttons, contrasting top stitching, flat-felled seams, turned and stitched hems, or even frayed hems, five-pocket styling, back patch pockets, cargo pockets, and even logo patches or stitching on the back. Why has “trouser jeans” become a name for these? What are the formerly named trouser jeans now called?