What is "Core E", "LOW", "SL"?

What is "Core E", "LOW", "SL"?

Just a reminder; for people like my brother, who might be reading this blog-"Sonlight" is the main spine of our homeschooling curriculum-Sonlight is a company that sells books and instructions on how to teach your children at home.-"Core E" is the specific level we are in right now.  If we were in public school; Dd would be put in a grade 4th, 5th, or 6th grade.  With Sonlight (which is abbreviated "SL") you don't have 'grades' you have history steps, and each step is called a 'Core'.  We've finished Core A, B, C, D, and are working on Core E now.  Core E is the second part of a two-part series on American history.

What is a "LOW"? L-Left, O-Overs, W-Week--just like you have left-overs with your meals, I have left-overs with my lessons.  I'm just not quite so ready to move on yet; and want to slow down the pace.  Especially with big history points, I want to SLOW down and let this info sink in.