* Intrusive rock is formed when magma (molten rock) cools and solidifies beneath the Earth's surface.
* Plutonic rock is a specific type of intrusive rock that cools and solidifies at a depth of at least 1.5 km. This is because the prefix "pluton" refers to a large body of intrusive igneous rock.
So, while plutonic is a more specific term for a type of intrusive rock, intrusive is a broader term that encompasses all rocks that solidify from magma below the surface.
