A "pinstripe pattern" refers to a design often seen on clothing or fabrics, where thin vertical lines are evenly spaced, resembling tiny pins or needles. Full definition
The interior features a unique pinstripe pattern on the upholstery and a leather - wrapped steering wheel and gear knob, all of which are enhanced by orange stitching. (overdrive.in)
For instance, when I rolled up the sleeves on this navy blazer, I noticed the navy / white pinstripe pattern. (curlycraftymom.com)
That tells you that grey may be that seasons new black along with pinstripe patterned trousers with a loose fit reminiscent of the type of trousers that actress Lauren Bacall wore in the 1940's. (thefashionablehousewife.com)