Common abbreviation for インフルエンザ, used in everyday conversation and news.
See also: インフルエンザ
I caught the flu last week and missed school.
The flu is going around this winter.
I got a flu shot.
The flu is spreading more than usual this year.
I got a flu shot before winter.
My brother is off work because of the flu.
Abbreviation of インフルエンザ, from English 'influenza'.