1. produced under conditions involving intense heat

- igneous rock is rock formed by solidification from a molten state; especially from molten magma

- igneous fusion is fusion by heat alone

Similar word(s): pyrogenic, pyrogenous

2. produced by the action of fire or intense heat

- rocks formed by igneous agents

Similar word(s): eruptive

3. like or suggestive of fire

- an igneous desert atmosphere

Similar word(s): hot, fiery