rain-fed

The compound adjective "rain-fed" is a transparent modern English formation. Its first element, "rain," descends from the Proto-Germanic regna-, a term for precipitation. The second element, "fed," originates from the Old English verb fēdan, meaning to nourish or supply with food, itself derived from the noun fōda (food). The compound's logic is directly metaphorical: just as a child or animal is "fed" to be sustained, land or crops are described as being "fed" by rain. This construction efficiently creates a technical term in agriculture and environmental science, specifying a system dependent on natural rainfall for its water supply, in contrast to irrigated or groundwater-dependent systems.

Structure: rain (water from clouds) + fed (provided with food/sustenance) - rain: From Old English regn, rēn (rain), of Germanic origin; related to Dutch regen and German Regen. Functions as a noun root denoting precipitation. - fed: Past participle of the verb feed, from Old English fēdan (to nourish), from fōda (food). In this compound, it functions as an adjective-forming element meaning "supplied or sustained by."