Let me create a simple link to Bitbake, poky and recipes.
Poky is the reference system of the Yocto project and consists of a set of tools and metadata. Poky is platform independent and cross-compiles using the Bitbake Tool , OpenEmbedded Core and the default metadata set. Poky’s primary goal is to provide all the features with built-in developers.

Bitbake - , Python Shell script, . . .
- . Python Shell script. Poky OpenEmbeddded Core, meta-yocto meta-yocto-bsp
: Linux Yocto