Final answer:
The rounded projection posterior to the external auditory meatus is called the mastoid process.
Step-by-step explanation:
The rounded projection of the temporal bone located posterior to the external auditory meatus is known as the mastoid process. This prominent feature of the temporal bone can be easily felt as a bump on the side of the head just behind the earlobe. The mastoid process, besides serving as a landmark,
also functions as an attachment site for certain muscles of the neck. In the interior aspect of the skull, the temporal bone includes the petrous ridge, which contains cavities for the middle and inner ear structures.