diametral

Supposing you wanted to know the number of teeth in a gear where the pitch diameter and the diametral pitch are given.

The circumferential pitch is of course got by dividing the diametral pitch by π.

Diametral spines crossed loosely in the centre of the spherical or irregular roundish central capsule.

Of course every diametral spine pierces the capsule twice, at two points diametrically opposed.

In the following table are given various arc pitches, and the corresponding diametral pitch.