What is the correct definition of lung cancer?

I searched up the definition of lung cancer, and went to many websites and they all give me a different meaning of the word.

Lung Cancer Nursing Considerations and Management

Nursing Considerations for Lung Cancer Patients

Preventing Lung Cancer: What You Need to Know

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Breakthroughs in Lung Cancer Research

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Understanding Lung Cancer

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Early Detection and Treatment of Lung Cancer

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Living with Lung Cancer: A Survivor’s Story

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Is the smoke in cigarettes what really will cause lung cancer?

What can you bring foodwise or giftwise to a friend with lung cancer?

How long does a person smokes before she gets heart disease/lung cancer?

For how long have people known about lung cancer?

what is the survival rate for stage 4 lung cancer with mets to the bone?

How does genetics play a role in lung cancer?

Where can someon go to get tested for lung cancer in los angeles or california ?

What are the causes for lung cancer?

Can a person get lung cancer even if he or she have quit smoking?

Is there a cure for lung cancer through alternative medicine?

Is there any hospital in the Philippines offering cryosurgery to treat lung cancer?

When should a doctor check for lung cancer?

What is the association between smoking and dying of lung cancer?

What signs do you look for when someone is dying of lung cancer and their time is almost up?