Oceanic crust, pillow lava, sheeted dyke complex কী?

The oceanic crust is the crust made at ocean ridges: 6 to $7\,\mathrm{km}$ of basalt and gabbro, from the sea floor down to the Moho, beneath a cover of sediments. Pillow lava is lava erupted under water, made of rounded, interconnected tubes and lobes, each with a glassy skin chilled by the sea. A sheeted dyke complex is a layer made almost entirely of parallel vertical dykes, each intruded into the previous ones.