What is a jelly polish?

I know that there are some nail polish fanatics who read my blog (waves to my peeps!) but I also know that not everyone who reads Nouveau Cheap is freakishly obsessed with nail polish. For the casual nail polish fan, some of the terminology within the nail community might be a bit confusing, which is completely understandable (I just recently found out what "tacoing" means--if you don't know,