Flu: meaning, definitions and examples

Used in everyday conversation to refer to a common viral illness that causes fever, chills, muscle aches, cough, congestion, runny nose, headaches, and fatigue.

• I caught the flu and had to stay home from work for a week

Used in medical or formal contexts to describe the viral infection that affects the respiratory system, often specified by type (such as Influenza A or B).

• The doctor confirmed that she has Influenza A, which is more severe than a regular flu

Used broadly to describe any infection caused by a virus, including but not limited to the flu.

• She was suffering from a viral infection, which caused her to feel fatigued and feverish

Used generally to describe any illness that affects the lungs and breathing, not limited to viral causes.

• The patient was diagnosed with a respiratory illness and was immediately given medication

Refer to the influenza virus that causes specific symptoms like fever, chills, muscle aches, cough, and fatigue. Use it when you talk about an illness diagnosed by a healthcare professional.

• I was diagnosed with the flu last week and had to take some days off work
• During flu season, many people get vaccinated to prevent it

A general term for any illness, not specific to the flu. Suitable when you want to mention someone not feeling well without specifying the illness.

• I can't come to the party tonight because I'm feeling sick
• He called in sick to work this morning

A more formal way of indicating that someone is sick or not feeling good. It's often used in written or polite contexts.

• She has been unwell for a few days now
• Please notify us if your child is feeling unwell

An idiomatic expression implying a mild illness or not feeling well. It's often used in a casual conversation.

• She won't be joining us today; she's feeling a bit under the weather
• If you're feeling under the weather, it's best to rest