Final answer:
The conversion of sediment into sedimentary rock through the processes of compaction and cementation is known as lithification.
Step-by-step explanation:
The process of turning sediment into a sedimentary rock is called lithification, which consists of two main stages: compaction and cementation. Compaction happens when the weight from layers of sediment presses down, reducing the space between sediment grains. Cementation occurs as minerals precipitate out of water being squeezed from the sediments, effectively gluing the particles together. Ultimately, these processes transform loose sediment into solid sedimentary rock, which can be clastic, chemical, or organic in nature.