Question

What does moho stand for?

Answer 1

It's the Mohorovic Discontinuity, the boundary between the crust and the mantle.

Explanation:

Scientists are not sure exactly what the Moho really is, but seismic evidence suggests that there is a change in the composition of the bedrock. At the high pressures deep inside the Earth, different minerals and therefore different rocks become stable, so such a change in composition is quite plausible.

For more about the Moho, see here:

https://en.m.wikipedia.org/wiki/Mohorovi%C4%8Di%C4%87_discontinuity