Is PDO_OCI (PHP PDO using Oracle Instant Client) classed as ODBC?

I have a question that's been concerning me for some time.

We use Oracle at our company and we're about to upgrade to a newer release. I understand that Oracle have some additional licensing if you wish to connect to the database via ODBC.

My question is, we have a web application that connects to the Oracle database using PDO_OCI (PHP PDO using the Oracle Instant Client) - is this classed as accessing the Oracle database via ODBC?