Flu vs. flue

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Flu, short for influenza, refers to a contagious viral infection involving respiratory inflammation and fever. The word is also used more generally for a range of illnesses involving similar symptoms. A flue is a pipe, duct, or tube through which exhaust gases from a fireplace, furnace, or boiler exit a building. There’s also a type of fishing net called a flue.

Flue is an old word. Its etymology is mysterious, but its earliest known instances in English are from nearly five centuries ago.1 Flu was sometimes spelled flue when it first emerged in the early 19th century (a century or so after influenza), but flu has now been the standard for over a century.2



For most people, financial housekeeping is about as desirable as getting a flu shot. [Globe and Mail]

A new report says the London Olympics will increase the already ”extreme” risk of a flu pandemic spreading in Britain. [Sydney Morning Herald]

But then the Yankees were forced to make even more changes when Mark Teixeira was a late scratch because of flulike symptoms. [New York Times]


There was a mud-brick bed, heated by a flue from the cooker. [Guardian]

The flue? It’s actually an irrigation pipe. [Los Angeles Times]

The deadly fumes leaked out of the dodgy boiler flue pipe fitted 12 days earlier. [Telegraph]