Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English


English definition of “arachnoid”


noun [C]     /əˈræk.nɔɪd/ US  /əˈræk.nɔɪd/ specialized
the delicate covering of the brain or spinal cord : Symptoms associated with an arachnoid cyst can include headaches , nausea , seizures , and visual disturbances .The brain and nervous system
(Definition of arachnoid noun from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
Focus on the pronunciation of arachnoid

Word of the Day


relating to behaviour between people that is pleasant and friendly, often despite a difficult situation

Word of the Day


Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More