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noun

CFS

see-ef-ES

CFS (noun) means Chronic fatigue syndrome: a long-term illness whose central feature is severe exhaustion that is not relieved by rest and worsens after physical or mental exertion, usually accompanied by unrefreshing sleep, pain and difficulty concentrating. Example: “She was diagnosed with CFS after two years of unexplained exhaustion.”

noun
1
Chronic fatigue syndrome: a long-term illness whose central feature is severe exhaustion that is not relieved by rest and worsens after physical or mental exertion, usually accompanied by unrefreshing sleep, pain and difficulty concentrating.
"She was diagnosed with CFS after two years of unexplained exhaustion."
"CFS is now more often called ME/CFS in clinical guidance."
2
technical Cubic feet per second: a unit measuring the rate of flow of a liquid or gas, used especially for rivers and water systems.
"The river was running at 12,000 cfs after the storm."
3
computing Completely Fair Scheduler: the process scheduler used by the Linux kernel to share CPU time between running tasks.
"CFS replaced the older O(1) scheduler in Linux 2.6.23."

How to Use CFS

Learner’s notes

In plain EnglishUsually a long-term illness that causes crushing tiredness that rest does not fix.

When to use it

Written uppercase for the illness, lowercase cfs for the flow unit.

Memory tip

Do not confuse CFS with CSF. CSF is cerebrospinal fluid, the liquid around the brain and spinal cord — an easy and consequential typo in medical writing.

Trace the full origin ↓
Easily confused with
ME fibromyalgia long Covid CSF (cerebrospinal fluid)
Common pairings
diagnosed with CFS ME/CFS living with CFS peak flow in cfs
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Fill the Gap

Can you complete this real example?

She was diagnosed with _____ after two years of unexplained exhaustion.

Etymology

An initialism; the expansion depends on context, most commonly chronic fatigue syndrome or cubic feet per second.

Origin: English

ME myalgic encephalomyelitis ME/CFS chronic fatigue syndrome

Related Words

Frequently Asked Questions

What is the difference between CFS and ME?

They largely describe the same illness under different names. ME (myalgic encephalomyelitis) is the older term and is preferred by many patients because chronic fatigue syndrome sounds like ordinary tiredness. Health services increasingly write ME/CFS to cover both.

Is CFS the same as being tired all the time?

No. The defining feature is post-exertional malaise — a disproportionate crash in the hours or days after activity that ordinary rest does not fix. Ordinary tiredness improves with sleep; CFS characteristically does not.

What does cfs mean in measurements of water?

Cubic feet per second, the volume of water passing a point each second. It is the standard unit for river flow and dam discharge in the United States; metric countries use cubic metres per second instead.

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Definitions: FreeDict original editorial · etymology from FreeDict original editorial