Definition of eurypterid
: any of an order (Eurypterida) of usually large aquatic Paleozoic arthropods resembling scorpions and related to the horseshoe crabs —called also sea scorpion
Origin and Etymology of eurypterid
ultimately from Greek eury- + pteron wing — more at feather
First Known Use: 1871
Seen and Heard
What made you want to look up eurypterid? Please tell us where you read or heard it (including the quote, if possible).