Flu

How to spell flu

3 letters · 1 syllable

How to pronounce flu

What does flu mean?

1. nounA contagious viral infection, short for influenza, causing fever, aches, and respiratory symptoms.

Flu in a sentence

• Half the office caught the flu during the winter outbreak.

• The doctor recommended an annual flu vaccine for older patients.

Where does flu come from?

Language of origin: Italian

Flu is a casual shortening of influenza, which English borrowed from Italian in the eighteenth century. The Italian word literally meant 'influence', from the medieval Latin influentia, the same root that gives us the word influence itself; physicians once blamed epidemics on the supposed influence of the stars and planets, so an outbreak was an influenza, an 'influence'. By the 1830s English speakers had clipped the long word down to flu, originally often written with an apostrophe as 'flu to mark the dropped syllables. The spelling trap is that this short, ordinary-looking word sounds exactly like flew, the past tense of fly, and flue, a chimney pipe, yet it keeps its bare three-letter form with no silent letters at all.

How the word is built

• flu (clipped from influenza; Italian for 'influence', the supposed astral influence on disease)

Words that sound like flu

They sound the same but mean different things, so the meaning decides which spelling to write.

• flew: Past tense of fly: moved through the air, or travelled by aircraft.