dol·er·ite \ˈdäləˌrīt\noun (-s) Etymology: French dolérite, from Greek doleros deceitful (from dolos deceit) + -ite; from its being easily mistaken for diorite — more at tale 1.: a coarse basalt 2.Britain: diabase 3 3.: a dark igneous rock whose constituents are not determinable megascopically • dol·er·it·ic\|dälə|rid.ik\adjective