Someone who talks a load of crap for an extended period of time and does not know when to shut up!! The action is known as crusting. Frequently overused by some people which in itself is crusting!!
Steven - I saw the other day on this website that if you stand instead of sit during most of your daily activities you burn an extra 37 calories a day....how cool is that??!!
Fred - Dude your crusting, i've never heard anyone as crusty as you in my life....you are the definition of crust!!!
This layer is asls considered part of the "Lithosphere" which consists of the upper mantle and the crust.
"litho" translated in Greek means "rocky". Stating that these two are both rock and closely related in cheical composition.