What it means
A clean, everyday way to say something’s excellent and properly high quality. You can slap it on food, service, work, gear, a performance, whatever’s impressed you. It sounds warm and solid without going full hype-beast, so it’s handy when you want to praise something hard but still keep your feet on the floor.
Usage examples
"How was that new curry house then? Top-notch, mate. Staff were sound, naan was massive, and I’m still sweating like I ran the London Marathon."
"The food at that little place is top-notch, easily the best meal we have had all year."
"She did a top-notch job on the report, not a single thing to fix."
"That little hotel was top-notch, honestly. Proper comfy bed, no weird stains, and the breakfast actually had some dignity."
"Fair play, your mechanic’s top-notch. Car’s running sweet now and he didn’t even try to fleece me."
Where it comes from
Top-notch grew out of notch meaning a cut or mark used for ranking or keeping score. By the late 1800s, top-notch was already being used in English for the highest class or grade. The image is nice and plain: if something hits the top notch, it’s right up at the best level.