What does cephalitis mean?
Cephalitis is a noun meaning inflammation of the brain, a condition more familiar to modern readers under its current name, encephalitis. Built from the Greek roots kephalē ('head') and -itis ('inflammation'), it belongs to a large family of medical terms describing organ-specific inflammation. The word appeared regularly in medical writing from the eighteenth and nineteenth centuries, when physicians used it to describe febrile illnesses marked by headache, fever, confusion, and sometimes seizures or death. As neurological science advanced, encephalitis — which specifies the brain itself rather than the head generally — became the preferred term, and cephalitis survives today mostly in historical texts and older case reports. For general readers, encountering cephalitis is most likely in classic literature, archival documents, or histories of medicine, where it signals a serious, often life-threatening brain infection. Though obsolete in the clinic, the word remains a clear illustration of how Greek combining forms shaped English medical vocabulary.
nounInflammation of the brain; a chiefly medical term, now largely replaced in clinical use by the synonymous 'encephalitis'.
- Medical: inflammation of the brain tissue, typically caused by viral infection; now usually called encephalitis.
"The physician's nineteenth-century case notes recorded the patient's fatal bout of cephalitis."
"The autopsy report attributed the death to acute cephalitis following measles."
"Victorian medical journals frequently described cases of epidemic cephalitis during the summer months."
A rare Latinate plural following the pattern of words ending in -itis (as in 'arthritides'); in practice the singular is almost always used, even when referring to multiple cases.
"Nineteenth-century textbooks catalogued various cephalitides alongside other inflammatory diseases."
Before doctors settled on 'encephalitis', they literally said the brain was inflamed by calling it 'head-itis' — cephalitis is Greek for exactly that.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of cephalitis
Cephalitis derives from ancient Greek: kephalē, meaning 'head', combined with the suffix -itis, denoting inflammation. The same Greek root gives English a cluster of anatomical terms such as cephalic, cephalopod, and hydrocephalus. The word entered English medical vocabulary as part of the broader adoption of Greek-based disease nomenclature, becoming established by the early modern period. Its decline came as encephalitis, with the more precise root enkephalos ('brain'), displaced it in twentieth-century clinical usage.
How cephalitis is actually used
Cephalitis is a historical and technical term found mainly in older medical literature; modern clinicians say 'encephalitis'. It carries a formal, clinical register and would strike most readers as archaic today.
Easily confused with cephalitis
Encephalitis is the standard modern term for inflammation of the brain, while cephalitis is an older synonym that literally means inflammation of the head.
Cephalgia means headache — pain in the head — whereas cephalitis means actual inflammation of the brain.