|Definition - John McWhorter's term for what is more formally called periphrastic DO, the syntactic use of do and don't in constructions like Do you want to eat some ice cream?|
Etymology - The term was coined by McWhorter in his book Our Magnificent Bastard Tongue: The Untold Story of English. He believes that it entered Old English through contact with Welsh and Cornish, both of which have similar constructions.
I contacted him to confirm whether he had coined the term. Here's what he said:
"Meaningless do is something I just made up to highlight that we are dealing with a DO that has a syntactic but not semantic use. I never actually thought of it as a "term" -- linguists among themselves usually call it periphrastic DO or refer to it via what it does, discussing "DO support." Those struck me as too prickly and opaque to work in a book meant to be read for pleasure….