English Regional, Midlands, Scottish, Northern
1 Small stunted trees or bushes collectively; a thicket. Now Scottish.
2 Broken bricks or stones, rubble; waste material; (more generally) rubbish. Now English regional.
3 Shale, occurring in a thin stratum, often found just above the coal seam.
Middle English (in an earlier sense). Probably partly from Anglo-Norman ramail, ramaile, ramayle, ramale, from rame branch + -elle.
Ronnie rambled through the rammel and the rubble. A kid can make a playground from just about anything.