piggyback tax
n.— «Mr. Cohen said he’s never supported a cell phone tax or boosting the county’s portion of the income tax, often called the piggyback tax.» —“Negative ads fill last days of campaigns” by Jeff Horseman The Capital (Annapolis, Maryland) Nov. 5, 2006. (source: Double-Tongued Dictionary)
Further reading
The owner of a Berlin, Maryland, produce stand wants to know: When a customer is buying four ears of corn, should they say I have four corn or I have four ears of corn? Corn is a mass noun that can also be counted as a plural, just as we might say I...
The words tough, through, and dough all end in O-U-G-H. So why don’t they rhyme? A lively new book addresses the many quirks of English by explaining the history of words and phrases. And: have you ever been in a situation where a group makes...