Glossary of Terms

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Lung cancer

Cancer which has originated or started in the lung

Lung metastasis

Cancer which has started in another organ and spread to the lung

Chronic obstructive pulmonary disease (COPD)

A lung disease that is usually caused by smoking which causes shortness of breath (SOB) and cough, often with sputum production. 


A lung disease that often develops in children but can start in adulthood is due to inflammation of the airways in the lungs. This causes shortness of breath, cough, and wheezing. 


Inflammation of the covering of the lung (the pleura). This causes sharp chest pain while breathing and is most commonly caused by infection.

Obstructive Sleep Apnoea (OSA)

Repetitive obstruction or blockage of the upper airway during sleep causes frequent awakenings from sleep. This results in poor-quality sleep leading to sleepiness during the day. 

Central sleep apnoea (CSA)

When a person’s breathing slows down or stops during sleep. It occurs while their upper airway remains open as opposed to obstructive sleep apnoea where the airway blocks the breathing.

Onset Insomnia

The inability to fall asleep when you go to bed.

Maintenance insomnia

Waking up during the night and having trouble getting back to sleep


A category of conditions caused by inhaling something that injures your lungs. Examples include black lung disease from coal dust and asbestosis from asbestos dust.

Tuberculosis (TB)

A specific lung infection that needs careful treatment to cure. Because it may be passed from person to person, it may be necessary to contact people who have been in contact with an infected patient. Most TB in Australia comes from Asian and Middle Eastern countries. It may lay dormant for many years is a person’s lungs.

Sleep paralysis

A common benign symptom where there is the temporary inability to move or speak usually occurring when waking up from sleep.


A very brief period of sleep, lasting only a few seconds. Microsleeps occur most frequently when a very sleepy person is trying to stay awake.

Sleep debt

An individual’s accumulated lack of sleep from insufficient time asleep, regardless of cause. This may be due to going to bed too late or getting up early to go to the airport or to work.

Sleep latency

How long it takes a person to fall asleep from the onset of the potential sleep period; for instance, time measured from turning the lights out to the onset of sleep.


An abnormal disruption from sleep resulting in an abnormal experience or physical event. For example, sleep walking, sleep talking, night terrors, bed wetting etc

Circadian Rhythm disorders

Also known as sleep-wake cycle disorders. These are problems that occur when your body’s internal clock, which tells you when it is time to be asleep or awake is out of sync with your environment. For example, when a teenager stays up late and sleeps in, this is a delayed phase circadian rhythm. Shift work also causes a circadian rhythm disorder.


Difficulty breathing when lying down flat. This is may be due to heart failure or obesity.

Pulmonary rehabilitation

An exercise and educational program for people with lung diseases to enable them to manage their condition and optimise their exercise capacity.

Lung fibrosis or pulmonary fibrosis

Lung fibrosis is the general term for a number of different diseases that all result in excessive scarring of the lung. This often causes slowly worsening breathlessness and cough.


A lung disease which results in shortness of breath due to destruction of the lung tissue. This is usually due to smoking.


A chronic sleep disorder characterised by overwhelming daytime sleepiness and sudden attacks of sleep. People with narcolepsy often find it difficult to stay awake for long periods of time, regardless of the circumstances.

Pulmonary oedema

A condition caused by excess fluid in the lungs. This fluid collects in the numerous air sacs in the lungs, making it difficult to breathe. In most cases, heart problems cause pulmonary oedema.