A poke cake is a single-layer cake that is baked and then poked with a skewer to create numerous small, deep holes, over which a liquid or creamy syrup or sauce is poured. The liquid seeps into the holes, imparting moistness, flavor, and sometimes color throughout the cake.
While the technique of pouring a syrup over a cake to add flavor has been well-known for at least a century, the term "poke cake" appears to have been invented by the makes of Jell-O gelatin in the 1970s as a way to encourage the use of Jell-O as a colorful pourover for boxed cake mix.