A clear lacquer that dries to a smooth hard glossy finish. The term is applicable in many scopes (e.g. furniture), but it's mostly in reference to nail polishes.
When doing your nails, a glossy top coat isn't optional, it's absolutely mandatory!
Abigail: Hey girl how's it gā OMG was is that??
Jess: What is what?
Abigail: Your nails....
Jess: Yeah...? What about them?
Abigail: They glossyyy af š
Jess: Ohhhh, that's only because I used my ļ½ļ½ļ½ļ½ļ½ļ½ ļ½ļ½ļ½ ļ½ļ½ļ½ļ½
Abigail: OMGGGG I think I'm in love ššš