Arachnoid may refer to:
Relating to arachnids Arachnoid (astrogeology), a geological structure found only on the planet Venus Arachnoid (botany), referring to organs with a cobwebby exterior appearance Arachnoid granulation, small protrusions of the arachnoid mater Arachnoid mater, a layer of the meninges, membranes that contain the central nervous system
See also Arkanoid, an arcade game