原っぱ
はらっぱ · harappa · JLPT N1 · noun
plain
🌾 はら (hara, field) + ぱ (pa, open flat space): a field that is simply open ground
原 means original or plain ground, and っぱ is a colloquial form of 端 or 場, a flat stretch. Together they name an open, unbuilt plot of grass or wasteland.
原 — cliff 厂 + spring 泉 (white 白 + water 水)
Originally a pictograph showing a spring of water flowing out from beneath a cliff, depicting the source of a stream. From this concrete image of a water source, the meaning extended to 'origin,' 'source,' and 'original.' A separate character 源 was later created with the water radical 氵 to keep the literal 'spring' sense.