I've seen the phrase OWA used around here on several questions, what does it stand for? Is it a standard feature?
It stands for Office Web Apps.
It's a service that add certain features to one or multiple on-premise farms (2013) by configuring an additional server to host the OWA service and then set up a connection to any SharePoint 2013 farms where the service is desired.
The biggest benefits is the ability to edit documents in the browser or create new ones. (Excel, Word, PowerPoint). It is included by default in O365.
In the past before Office Web Apps, OWA can also refer to Outlook Web Access (which is the browser based Outlook for accessing mail in Exchange).
This was renamed to Outlook Web Apps, and again to Outlook On the Web.
Full Form "Office Web Apps" or "Outlook Web Access"