What does "flu" mean?

1. (influenza) a common illness that gives you a fever, a headache, and makes your muscles ache. 2. (stomach illness) an illness that makes you feel sick to your stomach, often causing vomiting.

How do you use "flu"?

Usually used with the definite article 'the'.

Is it correct to say "I have a flu."?

No — say "I have the flu.". In English, we almost always use 'the' with flu when talking about being sick.

flu

US //ˈfɫu// UK //flˈuː// flu

1 influenza (n.)
A2 Elementary Medicine

a common illness that gives you a fever, a headache, and makes your muscles ache.

an acute respiratory infection caused by influenza viruses. Uncountable in general usage; often takes the definite article 'the'.

Example

I couldn't go to work because I had the flu and a high fever.

Example

Public health officials urged vulnerable populations to receive their vaccinations before the flu season reached its peak in mid-winter.

Usage

Usually used with the definite article 'the'.
- influenza
- grippe
Pitfall

I have a flu.

I have the flu.

In English, we almost always use 'the' with flu when talking about being sick.
2 stomach illness (n.)
B1 Intermediate Informal Medicine

an illness that makes you feel sick to your stomach, often causing vomiting.

a colloquial term for gastroenteritis or similar digestive upsets, though medically distinct from influenza.

Example

Half the kids in the class were out last week with a stomach flu.

Example

Although the patient described his symptoms as 'stomach flu', the physician suspected a bacterial infection from contaminated seafood.

Teacher's tip

Medical professionals prefer 'gastroenteritis' as 'flu' technically only refers to respiratory viruses.
- gastroenteritis
- stomach bug

Origin

Clipping of influenza.

Idioms1 entry

01
diplomatic flu
An illness feigned by one or more government officials or other public figures as an excuse for an absence really based on political factors.