短波
たんぱ · tanpa · JLPT N1 · noun
short wave
短 — arrow 矢 + bean/vessel 豆
Originally a phono-semantic compound: 矢 (arrow) gives the meaning, since arrows were used as a short measuring stick, while 豆 (an ancient stemmed vessel) supplied the sound. From 'short in length' the meaning broadened to 'short' in time, stature, or quality.