Is Android synonymous with Google or not?

If You are asking"Can Android Live without Google" then Your answer is Yes.
Google may Have Created Or Upgraded it But the Developer community at XDA and Other Forums Such as Android Central Is Responsible for It's "Evolution"
 
Your question needs clarifying.

Google created the base operating system of Android.
The phone makers build launchers and services and apps at the medium and high levels of the computing system.
Google's part here is required.

Google also makes high-level apps for the Android phones. All of the Google apps are optional except for the Play Store app. While they are optional, meaning you don't have to use them, many of them are automatically installed on your phone as part of the licensing agreement with the phone makers.