This is the grammar of physics: the SI base units, the dimensional formula, significant figures, and the honest reporting of error.

Two instruments set the tone. The vernier caliper resolves L.C. = 1 MSD / N = 0.10 mm; the screw gauge resolves L.C. = pitch / n = 0.01 mm.

Everything mechanical reduces to three base dimensions, the plate [ M L T ] at the centre.