بِطَاحٌ بُطَّحٌ

[Many wide water-courses in which are fine, or minute, or broken, pebbles: the former word is plural of أَبْطَحُ or of بَطْحَاءُ]: a phrase like أَعْوَامٌ عُوَّمٌ. (As, A 'Obeyd, S.)