Till
Till explained in an easy to understand way:
Imagine cleaning out your refrigerator and finding a sticky residue left behind by spilled juice. Just like how the juice leaves behind a sticky film when it evaporates, a melting glacier deposits sediment as it retreats. The sticky residue is to the juice as the sediment is to the glacier; both are remnants left behind after the main substance (juice or ice) has disappeared.
Practice Version
Till: The sediment left behind by a melting glacier. Till. Till is a mix of rocks, sand, and clay deposited directly by a glacier.