What does FL mean in crocheting?

The abbreviation "FL" in crochet refers to "Front Loop."

The Front Loop is referring to the top of the stitch--the one you crochet into to create the next row. Generally you pull your stitch through both loops on the top of the stitch, however, you can also just use one of the two stitch "sides."

When you look at the top of a stitch, to me, it looks heart-shaped. There is a side of the "heart" that would be closer to you (the "front") and a side of the "heart" which would be further "away" from you (the "back" loop).

I found a photo which shows the anatomy of a crochet stitch, which will probably explain and show what I'm attempting to put into Words, much better that I seem to be managing in my "explaination."