Just a quick note to help myself remember: the jQuery $(…) syntax is a shortcut for the jQuery(…) function, but it may not always be the same.
Specifically, I was helping my sister debug some jQuery that wasn't behaving the way it should. After a couple of hours scratching our heads, the lightbulb finally came on–another library that was getting loaded on the page was overriding the $(…) function. Replacing our $(…) calls with jQuery(…) solved our problems. Sometimes it's best to just go with the formal syntax.