The boundary between Earth's crust and mantle is called what?

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Seismic waves reveal abrupt changes in rock properties where one layer ends and another begins, shown by a noticeable jump in wave speeds. The boundary between the crust and the mantle is called the Mohorovicic discontinuity, or the Moho. It marks a change from crustal rocks to mantle rocks, and wave speeds increase once you cross into the mantle due to higher density and different mineral composition. Depths vary: roughly about 30 km beneath continents and about 7–10 km beneath oceans, with larger variations in different regions.

Other terms refer to different boundaries: the Gutenberg discontinuity is the boundary between the mantle and outer core; the Lehmann boundary is between the outer and inner core; and the boundary commonly associated with the upper mantle and lithosphere (often called the lithosphere-asthenosphere boundary) is not the crust–mantle interface.