arm, viticultural term for that part of the vine’s woody framework from which the canes and spurs arise. The location of arms depends on the vine-training system used. They may be borne along cordons, positioned at intervals so that the buds, after pruning, are placed to space the bearing shoots desirably. Alternatively, the arms may be positioned on a short head at the top of the trunk as happens with some cane pruning systems. Arm is used interchangeably with cordon in some regions but if both are present, the arm is the shorter and the cordon is the longer.