HOW TO MAKE RBI PLURAL: Baseball season has started, so it’s a good time to answer questions from listeners who have asked how to make an abbreviation such as "RBI" plural. PRINCIPAL OR PRINCIPLE? Today we’re going to recall that the principal is indeed your “pal,” but we’ll also see that a principal can be so much more. In this episode we’ll talk about the various ways to use “principle”—that’s “p-l-e”—and “principal”—that’s “p-a-l.” RUN OF THE MILL. Why we say "run of the mill" instead of "run of the mine" or "run of the kiln." SPONSORS http://amazon.com/kindleforkids http://weebly.com/grammar AMAZON AFFILIATE CODE http://quickanddirtytips.com/amazon FOLLOW GRAMMAR GIRL Twitter: http://twitter.com/grammargirl Facebook: http://facebook.com/grammargirl Snapchat: http://snapchat.com/add/thatgrammargirl Pinterest: http://pinterest.com/realgrammargirl Instagram: http://instagram.com/thegrammargirl LinkedIn: https://www.linkedin.com/company/grammar-girl