Updated June 16th, 2019.
What’s “LERJ,” you might wonder. Well, in Microsoft Word, it’s simple:
⌘-L left-justifies a paragraph
⌘-E cEnters a paragraph
⌘-R right-justifies a paragraph
⌘-J justifies a paragraph (that is, it fully justifies it– left and right edges squared off)
Put it all together and that spells “LERJ.”
(They couldn’t use ⌘-C for Center because ⌘-C is used, by the System, for Copy.)
This works in Word 2008, Word 2011, Word from Office 365, and will probably keep working in Word forever.