This indicates an attempt to access Google services.
Google services cover the base domains of all Google services including Google Mail, Google Maps, Google Search, Google Docs, etc. Google is a multinational tech company that provides Internet related services. These include search engine, cloud computing, advertisements, emails, GPS.
Note: When enabled with the default Google application signatures in the database - like Gmail, Google.Drive, etc - this signature detects the Google domains that are not covered by the available database signatures.