1. The process by which unconsolidated sediments become sedimentary rock or are converted into coherent, solid rock.

Sediments typically are derived from preexisting rocks by weathering, transported and redeposited, and then buried and compacted by overlying sediments.

Cementation causes the sediments to harden, or lithify, into rock.

2. The physiochemical process that produces rock from sedimentary deposits.
3. A gradual process in which coal changes into bituminous shale or other rock.