One of the biggest difference between Cyanogen OS and CyanogenMod is how they’re made. While CyanogenMod is the community based Android ROM we all love, Cyanogen OS is built as a commercial product designed to be pre-installed on devices such as the WileyFox Storm and Yu Yureka. Another minor difference, the pre-installed applications. However starting today, some of those applications are making their way to CyanogenMod.
The “Cyanogen App Package” or “C-Apps” include can be installed on any Android device running CyanogenMod 12.1 from November 10th, 2015 and later. They could work on other versions, but they are not technically compatible. The apps package includes apps such as the Theme Store and Theme Chooser as well as AudioFX, Cyanogen Gallery, Email by Boxer, and Dialer with Truecaller. More apps will also be added as time goes on.
You’ll need to create a Cyanogen account to enable most of the functionality of these apps including accessing themes, TrueCaller functionality, and also the ability to remotely locate, wipe, and lock a phone.Source: CyanogenMod Blog