morphology
shoe, shoo
Fight Despotism
linguistics
essential, quintessential
portmanteau
hendiatris
If you search for ‘hendiatris’ on the Internet, you will find it easily, but if you search for it in a traditional dictionary, you probably won’t. It is possible that ‘hendiatris’ is a sort of back-formation from ‘hendiadys’, though it substitutes an affix rather than deleting one.