trilobite

UK: /ˈtraɪləˌbaɪt/ US: (trī′lə bīt′)

WordReference Random House Unabridged Dictionary of American English © 2025

tri•lo•bite  (trī′lə bīt′), n. 

1. any marine arthropod of the extinct class Trilobita, from the Paleozoic Era, having a flattened, oval body varying in length from 1 in. (2.5 cm) or less to 2 ft. (61 cm).

• Neo-Latin Trilobites, equivalent. to Greek trílob(os) three-lobed (see tri-, lobe) + -ītēs -ite¹
• 1825–35;

tri•lo•bit•ic (trī′lə bit′ik), adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

trilobite / ˈtraɪləˌbaɪt/ noun

1. any extinct marine arthropod of the group Trilobita, abundant in Palaeozoic times, having a segmented exoskeleton divided into three parts

Etymology: 19th Century: from New Latin Trilobītēs, from Greek trilobos having three lobes; see tri-, lobe

trilobitic / ˌtraɪləˈbɪtɪk/ adjective