I was watching an episode of Monk (S03E12), and in the first few minutes, the detective asks his assistant "Do you have a pliers?" That immediately struck me as weird, but later, towards the end of the episode, he makes the comment "This was cut with a scissors." The only place I've ever seen 'a scissors' was in old Peanuts cartoons, and I've never ever heard 'a pliers', but I guess it could make sense in a way.
I grew up saying a pair of scissors or pliers, which is weird in its own way, since it's a single object. I'm just wondering if anyone else has ever heard these terms.
I've heard both "a scissors" and "a pliers", but never "a pants" or "a glasses". If pressed, I don't think anybody would object to the proper term being "a pair of". Since you mention Peanuts, maybe it's a Midwest thing, since Charles Schulz grew up in Minnesota.
That could be it. I guess in the TV show, the writers are trying to show that Monk is an old fashioned guy who uses outdated terms.