|1.||[ adjective ] (geology) igneous rock that has solidified beneath the earth's surface; granite or diorite or gabbro|
|2.||[ adjective ] (geology) igneous rock produced by eruption and solidified on or near the earth's surface; rhyolite or andesite or basalt|
"volcanic rock includes the volcanic glass obsidian"
|3.||[ adjective ] erupting or tending to erupt|
"a geyser is an intermittently eruptive hot spring" "people fled from the erupting volcano"