1 definition by MeakPhronkey

Flu-Like Symptoms (fever, chills, headache, fatigue.)

The acronym is used heavily in the medical community. It has yet to have been thrown around wildly on television medical dramas, so it's not part of the pop-culture medical lexicon.
John has had FLS for three days now, I think he might have the flu!
by MeakPhronkey December 21, 2007
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