Definition of coalification in US English:
 coalification
noun ˌkōləfəˈkāSH(ə)nˌkōləfəˈkāSH(ə)n
The process by which plant remains become coal.
 Example sentencesExamples
-  Plant fossils of the lower Pease River Flora are preserved mainly as compressions and coalifications.
 -  Depending on the degree of carbon concentration and coalification, one differentiates between lignite, bituminous coal and anthracite.
 -  The humic organic matter of peat is also altered on burial, water and volatiles being lost during the process of coalification.