Cutting lasers as in making a host? Pitch is the measure of threads per inch of an imperial thread, usually something like this 1/4"-20 (this is the thread of a camera tripod)
Don't confuse pitch and lead though, metric threads are different. The second number of a metric thread is the measure of the advancement of the thread per one revolution. An aixiz lens is 9mmx0.5mm, so one turn of an aixiz lens will move the lens .5mm closer or further from the diode.
Hope this clears things up a little, assuming this is the pitch you are thinking of!
Pitch is often used to refer to the spacing between elements in a regular, periodic pattern. In this case, it sounds like they're just using radial coordinates (angle/distance on an arc) instead of cartesian coordinates to specify the distance between elements in a periodic pattern of holes.