I. ikˈstrüsiv, (ˈ)ek|s-, -üziv adjective
Etymology: extrus ion + -ive
: of, relating to, or produced by geological extrusion
volcanic eruptions and other extrusive phenomena
extrusive rocks formed after lava reached the earth's surface
— contrasted with intrusive
II. noun
( -s )
: a mass (as an igneous rock) produced by geological extrusion