Deltaic is an adjective used to describe something that is associated with or characteristic of a delta, which is a triangular shaped landform that forms at the mouth of a river where it meets the sea. There are several synonyms for the word Deltaic, including "fluvial," which means related to a river or stream; "estuarine," which refers to an environment where freshwater meets saltwater; and "alluvial," which means relating to or derived from alluvium, the sediment deposited by a river. Other synonyms include "deltic," "deltoid," "delta-forming," and "riverine," which all imply a connection or association with a deltaic environment.