Cosediment refers to the phenomenon in which two or more substances deposit together in sedimentary rock formation. There are several synonyms that can be used to refer to this process. One such word is concomitant sedimentation, which denotes the concurrent deposition of different materials in the same sedimentary sequence. Another useful synonym is synsedimentary deposition, which refers to the deposition of sediments occurring simultaneously with other geological or biological processes. Additionally, co-residence of different sedimentary materials can be described as co-deposition, neosoilization, or synchronous sedimentation, all of which refer to the act of depositing or settling together. These words can prove helpful in describing geological processes and phenomena that involve cosedimentation.