The outer core refers to the layer surrounding the central part of something. In particular, it most commonly refers to the outer layer of Earth's core, which is a hot and liquid portion located beneath the Earth's mantle. Full definition
The region is located right above the boundary between the hot liquid outer core and the stiffer, cooler mantle. (sciencedaily.com)
Those light elements would then rise into the liquid outer core, creating convection currents. (discovermagazine.com)
Every now and then the earth's magnetic field, which here points north and down, would reverse and point south and up, all due to the convection of the liquid outer core of the earth. (discovermagazine.com)