The term 'watering aid' can be summarized by the crossword solution of 'HOSE, ' which is a four-letter word. A HOSE is a flexible tube used to convey water from one place to another, and is commonly used in gardening and landscaping. It is also used for other purposes such as washing cars, cleaning driveways, and watering lawns. Hoses come in a variety of sizes and materials, and can be connected to a variety of accessories such as nozzles, sprinklers, and timers.