1) Cat breed 
The Chartreux is a rare breed of domestic cat from France and is recognised by a number of registries around the world. It is not recognised by the GCCF in the UK, ostensibly for being too similar to the British Shorthair, one of whose colours is a similar blue-grey. The Chartreux is large and muscular, with relatively short, fine-boned limbs, and...
• (n.) A Carthusian.
Char`treux' noun [ French] A Carthusian. 
The Chartreux is a French breed of shorthaired cat, not recognised in Britain where it is considered to be a blue British Shorthaired. The breed originated in the 1920s, and were first shown in 1931.