Wiktionary
n. The triad of nuchal rigidity (neck stiffness), photophobia, and headache, a sign of irritation of the meninges, as seen in meningitis, subarachnoid hemorrhages, etc.
WordNet
n. symptoms that mimic those of meningitis but without inflammation of the meninges
Wikipedia
Meningism is the triad of nuchal rigidity (neck stiffness), photophobia (intolerance of bright light) and headache. It is a sign of irritation of the meninges, such as seen in meningitis, subarachnoid hemorrhages and various other diseases. "Meningismus" is the term used when the above listed symptoms are present without actual infection or inflammation; usually it is seen in concordance with other acute illnesses in the pediatric population. Related clinical signs include Kernig's sign and three signs all named Brudzinski's sign.