The term 'ARACHNID' is an 8-letter word that can be used to describe both a scorpion and a tick. Arachnids are a class of arthropods, which are invertebrates with jointed legs and an exoskeleton. They have eight legs and two body segments, and they are found in many different habitats around the world. Scorpions and ticks are both examples of arachnids, and they are both known for their ability to inject venom into their prey.