Definitions

1. noun

A hypothetical or theoretical invertebrate animal resembling an arachnid, especially an arthropod of the subphylum Chelicerata, having four pairs of walking legs and no antennae.

“The discovery of the arachnidan species in the cave was a significant find for the scientific community.”

2. adjective

Relating to, resembling, or resembling arachnids, such as spiders or scorpions.

“The arachnidan features of the fossilized creature suggested a connection to its arachnid ancestors.”