الأبعاد الثلاثة، أعني الطول والعرض والعمق
The three dimensions: length, breadth and depth.
These name extension in three directions. The abstract notion of a line differs from that of a body: one-dimensional extension is prominent in the former, whereas a body is considered three-dimensional.
In the classical argument, extension and composition must be distinguished. One concerns directions and dimensions, the other constituents. The difference explains why some theologians require full dimensional extension while others treat composition as sufficient.