Emails and contacts are each a unique entity in VMA Emailer.
It is important to note the difference between an email and a contact. An email is a message itself which is sent TO a contact and a contact is a unique email address which has its own event history and log. Each email in the VMA Emailer system is unique, even if the same content is sent to multiple contacts, each message is considered a stand-alone entity and is tracked as such.
However, the status of an email and the status of a contact can be very dependent on one another. For example, if a contact's status is "Invalid", then that will cause any emails to that contact to be "Suppressed". And vice versa, if a status of an email is "Unsubscribed" then that will cause the status of the contact to also change to "Unsubscribed".
Here are some helpful guides that provide details on email statuses and contact statuses.
Email Delivery Statuses
An email will only ever be in one status at any given time. But most emails will have several statuses over its life cycle. If an email bounce, it has a status of "Bounced". But there are many different types of bounces and the Bounced Error Categories And Filters guide goes into detail on the different bounce categories and what they mean.
Contact Statuses
Each unique address is considered a "Contact". Each contact is tracked individually and has its own status. The status of the contact plays an important role in the delivery of email to the contact.