* Descriptive: "The fishing boats bobbed gently at the river mouth, where the freshwater met the salty ocean."
* Action: "The explorer carefully navigated his canoe through the turbulent waters at the river mouth. "
* Ecological: "The river mouth is a critical habitat for many species of fish, as it provides a transition zone between freshwater and saltwater."
* Historical: "The ancient city was strategically built at the river mouth to control trade routes and access to the sea."
* Figurative: "Her words were like a river, flowing freely and powerfully until they reached the river mouth of her heart, where they poured out in a torrent of emotion."