from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Situated or occurring beneath the arachnoid membrane, or between the arachnoid and the pia mater: subarachnoid space; subarachnoid anesthesia.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Located or occurring below the arachnoid mater, often specifically between the arachnoid membrane and the pia mater
from the GNU version of the Collaborative International Dictionary of English
- adj. Situated under the arachnoid membrane.
from The Century Dictionary and Cyclopedia
- Situated beneath the arachnoid—that is, between that membrane and the pia mater: as, the subarachnoid space.
sub- + arachnoid (Wiktionary)