Merriam-Webster's Word of the Day
This is a podcast to which one can subscribe.
'Build your vocabulary with Merriam-Webster's Word of the Day! Each day a Merriam-Webster editor offers insight into a fascinating new word -- explaining its meaning, current use, and little-known details about its origin.'
According to one user, "This podcast really delves deep into word origins, allowing listeners not only to know what a word means, but why."