buhr·stone also burr·stone 
(bûrstōn′)
(bûrstōn′)n.
A tough, silicified limestone formerly used to make millstones. It is typified by the presence of multiple cavities that originally housed fossilized shells.
[Variant of BURR1 + STONE.]
- machete
- Machiavelli
- Machiavellian
- Machiavellianism
- Machiavellism
- Machiavellist
- machicolate
- machicolation
- machinable
- machinate
- machination
- machinator
- machine
- machine bolt
- machine code
- machine finish
- machine gun
- machine-gun
- machine gunner
- machine language
- machine pistol
- machine-readable
- machinery
- machine screw
- machine shop