hydrocephalus

noun

hy·​dro·​ceph·​a·​lus ˌhī-drō-ˈse-fə-ləs How to pronounce hydrocephalus (audio)
variants or less commonly hydrocephaly
: an abnormal increase in the amount of cerebrospinal fluid within the cranial cavity (as from obstructed flow, excess production, or defective absorption) that is accompanied by expansion of the cerebral ventricles and often increased intracranial pressure, skull enlargement, and cognitive decline

Examples of hydrocephalus in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Billy Joel’s wife, Alexis Roderick Joel, thanked fans and supporters on Monday for the outpouring of support following the Piano Man’s diagnosis of normal pressure hydrocephalus, a brain disorder. Joseph Wilkinson, New York Daily News, 26 May 2025 On Friday, Joel canceled all the concerts on his schedule after revealing a diagnosis of normal pressure hydrocephalus (NPH), a brain disorder where excess cerebrospinal fluid accumulates in the brain’s ventricles. Daniel Kreps, Rolling Stone, 25 May 2025 On Saturday, Brinkley – who was married to Joel from 1985 to 1994 – took to social media to share her support and offer words of encouragement as Joel prepares to battle normal pressure hydrocephalus (NPH), a rare disorder which affects his vision, hearing and balance. Christina Dugan Ramirez, FOXNews.com, 25 May 2025 Billy Joel has canceled all his concerts due to a recent diagnosis of normal pressure hydrocephalus, according to a post on his official Instagram. David Oliver, USA Today, 24 May 2025 See All Example Sentences for hydrocephalus

Word History

Etymology

New Latin hydrocephalus, from Late Latin, hydrocephalic, adjective, from Greek hydrokephalos, from hydr- + kephalē head — more at cephalic

First Known Use

1670, in the meaning defined above

Time Traveler
The first known use of hydrocephalus was in 1670

Browse Nearby Words

Cite this Entry

“Hydrocephalus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/hydrocephalus. Accessed 5 Jun. 2025.

Kids Definition

hydrocephalus

noun
hy·​dro·​ceph·​a·​lus ˌhī-drō-ˈsef-ə-ləs How to pronounce hydrocephalus (audio)
variants also hydrocephaly
: an abnormal condition in which an increased amount of cerebrospinal fluid causes an increase in the size of the ventricles of the brain and the size of the skull and the wasting away of the brain

Medical Definition

hydrocephalus

noun
hy·​dro·​ceph·​a·​lus -ˈsef-ə-ləs, British also -ˈkef- How to pronounce hydrocephalus (audio)
plural hydrocephali -ˌlī How to pronounce hydrocephalus (audio)
: an abnormal increase in the amount of cerebrospinal fluid within the cranial cavity (as from obstructed flow, excess production, or defective absorption) that is accompanied by expansion of the cerebral ventricles and often increased intracranial pressure, skull enlargement, and cognitive decline

More from Merriam-Webster on hydrocephalus

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!