Slacks, pants and suit pants much like Dockers, or different makers of cotton, synthetic materials pants, wool pants, flannel pants and good looking gown pants are acceptable. One of the best fundamental business informal outfits is a straightforward pair of cotton-mix trousers, a nice blouse or tank (floral and print tops are all the time good) with a reasonably cardigan layered over.
Move Dockers off the golf-course and in to the cubicle, making Dockers the go-to for appropriate enterprise informal attire.
Not enterprise-y, however never too informal, the notion of a refined but comfy office costume code is dangerously ambiguous, with out some concrete perimeters.
Jeans will match lower at the trouser waist, as will many modern cut chinos and gown slacks.
The definition of enterprise casual varies from group to group as each has its own office standards and expectations.