Yocto is a build system name. it will provides customized images.
e.g.: Bootloader, Linux, rootfs.
Poky: Poky is a “Reference distribution” to provide customized images.
Reference distribution: A `Distro` that provides a bitbake to compile All of your kernel,bootloader.and minimal packages for rootfs.
Examples: poky , yogurt, baryon,luv,luv-netboot,micro, oe-measured,yogurt-wayland e.g.,
-> Bydefault yocto provides poky Distro And this will have different versions.
clink here to kinow the yocto versions
-> You can create your own distro with reference to poky.
Examples: meta-agl, meta-resin*, meta-yogurt, meta-bec etc,.
So some people will use poky distro and some people will use agl, bec as distro depends on the board etc.,
After this distro you will create your own meta-layer for your board like wand board, beaglebone, Raspberry-pi,nitrogen boards, etc.,
Open-embedded core(meta-oe) is a main layer which gives more packages for your rootfs.
examples: meta-network, meta-python, meta-ruby etc.,
\__ recipes-* (*.bb files)