en·doc·er·as \enˈdäsərəs\noun Usage: capitalized Etymology: New Latin, from end- + -ceras : a genus (the type of the family Endoceratidae) of Ordovician and Silurian nautiloid cephalopods with a straight shell having a very large siphuncle and endocones and reaching a length of 12 feet • en·do·cer·a·tid\|endō|serəd.ə̇d\adjective or noun