Riverine is an adjective that refers to anything related to rivers. Synonymous to this term are words such as fluvial, aquatic, riparian, watercourse, and watery. Fluvial describes the features or processes of a river, while aquatic refers to anything living or found in the water. Riparian is a term used to describe areas near a river or stream bank. Watercourse, on the other hand, denotes a channel or passage of water. Lastly, watery is used to describe anything that contains or resembles water. Overall, these synonyms effectively capture the essence and concept of the term riverine.