ˈdīəˌbās noun
Etymology: French, from Greek diabasis act of crossing over, from diabainein to cross over, from dia- + bainein to go — more at come
1. archaic : diorite
2. chiefly Britain : an altered basalt
3. : a hypabyssal rock of the composition of gabbro but with an ophitic texture consisting of labradorite laths involved in a matrix of augite with magnetite a common accessory