Subduction occurs where the oceanic crust bends down towards the mantle at a convergent plate boundary.

Here's a breakdown:

* Convergent Plate Boundary: This is where two tectonic plates collide.

* Oceanic Crust: The denser, thinner type of crust found under the ocean.

* Mantle: The layer of the Earth beneath the crust.

When oceanic crust collides with either another oceanic crust or a continental crust, the denser oceanic crust is forced to bend and slide beneath the other plate. This process is called subduction.