pitch circle diameter

I was looking at some cranksets on British websites and noticed they
use pcd. And Cycling News has an article on the new Shimano compact
crankset with pipe bottom bracket and they used pitch circle diameter
in the article.

I know pcd is bcd and pitch circle diameter is bolt circle diameter.
But what does the pitch stand for? With the bolt I know it means the
chainring bolts. Do British/Australians use the word pitch for bolt?

http://www.cyclingnews.com/tech.php?...arrivals/11-17

From Sheldon's glossary:

http://www.sheldonbrown.com/gloss_p.html#pitchcircle

wrote:

I know pcd is bcd and pitch circle diameter is bolt circle diameter.
But what does the pitch stand for? With the bolt I know it means the
chainring bolts. Do British/Australians use the word pitch for bolt?

The Compact Edition of the OED (Complete text), 1971 says:

Pitch

VII. 25 (Mech) The fixed distance between successive points or
lines (?the distance at which these are pitched or fixed). a. The
distance between the centres of any two successive teeth of a
cog-wheel or pinion, or links or a gear-chain, measured along the
pitch-line or pitch-circle; the distance between successive paddles
of a paddle-wheel, measured on the circle passing through their
centres ... c. The distance between the centres of successive
rivets or stays ...

James Thomson