Orthis

1 definition found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Orthis \Or"this\ ([^o]r"th[i^]s), prop. n. [NL., fr. Gr. 'orqo`s
     straight.] (Zool.)
     An extinct genus of Brachiopoda, abundant in the Paleozoic
     rocks.
     [1913 Webster]