This is the 10156th most frequent Swedish word.
influensa
Influenza; the flu, a contagious viral infection affecting the respiratory system.
Here, 'influensa' is used as a noun to designate the medical condition known as influenza or the flu.
Jag har influensa och känner mig svag.
I have the flu and feel weak.
In this sentence, 'influensan,' with the definite article 'an,' identifies the specific ailment commonly spreading during the winter season.
Influensan sprider sig snabbt under vintern.
The flu spreads rapidly during the winter.
Here, 'influensa' is again used as a noun, referring to the disease and being explained through its symptoms.