arachnoid
/ə'ræknɔid/
Học thuậtThân thiện
Definition
Adjective:
- Relating to or resembling arachnids: Pertaining to the class Arachnida, which includes spiders, scorpions, ticks, and mites, or having a similar appearance.
- Resembling a spider's web; cobweb-like: Having a fine, delicate, web-like structure.
Noun:
- A member of the class Arachnida: An air-breathing arthropod, such as a spider or scorpion, characterized by having simple eyes and four pairs of legs. (Note: This usage is less common; the typical term is "arachnid").
- (Anatomy) The arachnoid mater: The middle of the three meninges, the membranes that envelop the brain and spinal cord. It is a delicate, web-like membrane located between the dura mater and the pia mater.
Usage Examples
Adjective:
- The plant's seed pods had an arachnoid covering of fine hairs. (The seed pods were covered with a delicate, web-like layer of hairs.)
- Under the microscope, the crystal structure appeared arachnoid. (The structure of the crystals looked like a spider's web.)
Noun (Anatomy):
- Cerebrospinal fluid flows in the subarachnoid space, which is below the arachnoid. (The fluid circulates in the space beneath the arachnoid membrane.)
- The surgeon carefully incised the arachnoid to access the underlying brain tissue. (The surgeon cut the delicate arachnoid membrane.)
Advanced Usage
"Arachnoid granulations": (Anatomy) Small protrusions of the arachnoid mater into the venous sinuses of the brain, which allow cerebrospinal fluid to re-enter the bloodstream.
- The blockage of the arachnoid granulations can lead to a condition called hydrocephalus.
"Arachnoid cyst": (Medicine) A cerebrospinal fluid-filled sac that develops between the arachnoid membrane and the brain or spinal cord.
- The MRI scan revealed a small, benign arachnoid cyst.
Variants and Related Words
- Arachnid (n): The more common term for a member of the class Arachnida (e.g., spider, scorpion).
- Arachnophobia (n): An extreme or irrational fear of spiders and other arachnids.
- Subarachnoid (adj): Located or occurring beneath the arachnoid membrane, especially the "subarachnoid space" containing cerebrospinal fluid.
- Arachnoidal (adj): An alternative adjective form meaning "of or relating to the arachnoid membrane."
Synonyms
- Adjective (web-like): Cobwebby, filamentous, gossamer.
- Noun (arachnid): (Use "arachnid" as the standard synonym).
- Noun (membrane): Arachnoid mater (full anatomical term).
Related Phrases
- Arachnoid mater: The full Latin-derived name for the anatomical membrane.
- Arachnoid villi: Another term for arachnoid granulations.
Adjective
- relating to or resembling a member of the class Arachnida
Noun
- air-breathing arthropods characterized by simple eyes and four pairs of legs
- the middle of the 3 meninges